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Base16, 32, 64 Encoding / Decoding
by Jeff Dunlap 19 Dec '08

19 Dec '08

I had really hoped to find something in boost but didn't. I looked on the web and found various routines to encode data and came across a pretty complete library that encodes and decodes base16, base32, base64. Most are for either base16 or base32 but CyoEncode by Cyotec covers the three of them and the source code is available online. The function parameters seem very unfamiliar to me, for example: unsigned long Base32Encode( void* dest, const void* src, unsigned long size ); unsigned long Base32Decode( void* dest, const void* src, unsigned long size ); There are no samples online so I don't know how to use it. Since I don't understand those function params above, I just came up with the code below (seems to encode and decode base64 correctly but not for base32, base16: // encode char * buf1; buf1 = new char [100]; const std::string s = "1010"; CyoEncode::Base16Encode(buf1, s.c_str(), s.length()); // CyoEncode::Base16EncodeGetLength(s.length())); std::cout << "[" << buf1 << "]" << std::endl; // decode char * buf2; buf2 = new char [100]; const std::string s2(buf1); CyoDecode::Base16Decode(buf2, s2.c_str(), s2.length()); std::cout << "[" << buf2 << "]" << std::endl; Can someone review the Base32Encode params and let me know how this is really supposed to be used? Thank you very much, Jeff -- ELKNews FREE Edition - Empower your News Reader! http://www.atozedsoftware.com

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Asking for feedback for book (in German) about the Boost C++ libraries
by Boris 19 Dec '08

19 Dec '08

I've written a book in German about the Boost C++ libraries and uploaded it to http://www.highscore.de/cpp/boost/. As this is the very first version it's currently only available in HTML. I would appreciate any feedback about the content, presentation, examples, typos :) etc. Thanks, Boris

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Is there a patch for "thread copy constructor is accessible" BUG in solaris.
by Maruvekere, Praveen (Contractor) 19 Dec '08

19 Dec '08

Hi , I had posted this in build list now I am posting this in users of boost list. Please help thanks in advance. -------- I have done the temporary fix to build the boost 1.37.0 as told in one of the solaris user forum thread http://forums.sun.com/thread.jspa?threadID=5326640 <http://forums.sun.com/thread.jspa?threadID=5326640> for the below said error sun.compile.c++ bin.v2/libs/thread/build/sun-5.9/release/link-static/threading-multi/thr ead.o "./boost/thread/detail/thread.hpp", line 344: Error, inaccessible: boost::thread::thread(boost::thread&) is not accessible from boost::move(boost::detail::thread_move_t<boost::thread>). 1 Error(s) detected. Do I need a patch to fix this? -PM-

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boost::interprocess, shared memory and multi-core
by QuitePlace 19 Dec '08

19 Dec '08

Shared memory or other constructs from boost::interprocess will be used on multi-core computers? Will it be a performance degradation if two processes are allocated to different cores versus one core? The same with threads? Another look at this question is - should one program the inter-process/inter- thread communication first and worry about multi-core later? Or something should be planned at the development stage?

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Re: [Boost-users] Buffering and ASIO
by Vadim Shmelev 19 Dec '08

19 Dec '08

> Good day. > I'm trying to read video data transferred by HTTP. I use the following function in order > to read HTTP header: > boost::asio::async_read_until(m_socket, m_headerBuffer, "\r\n\r\n", boost::bind(&CAXISParser::read_header, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); > , where m_headerBuffer is asio::streambuf object. During header parsing i can get video sample length. Now I want to read all video data in one function call, for example: > boost::asio::async_read(m_socket, boost::asio::buffer(pSample->GetBody(), m_currentSampleLength), boost::bind(&CAXISParser::read_body, this, pSample, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); >, where pSample is object with buffer for video data. There is problem that async_read_until captures > some data from video data, and that call's behavior is incorrect. How can i fight that problem? For example, how can i figure out number of bytes left in streambuf and copy them to my buffer, and then read rest with async_read? I'm will very appreciate for any advices. > It's not clear to me exactly what you're asking here. From what I can > tell, you have created a buffer of size m_currentSampleLength, and > asked ASIO to call CAXISParser::read_body when it has received this > many bytes. Is that what you intended to do? Is that what boost is > doing? Or is the problem something else? > > -----Scott. Hello, Scott. Sorry for bad english, i'm will try explain. Yep, there is problem. When i'm read HTTP header with acync_read_until, it consume header and some bytes from video data (i think). After i'm calculate video data length from header and trying read data with async_read. But it works incorrect as previous call async_read_until captures some bytes from video data and video data readed with async_read have wrong offset. How can i understand, the problem that async_read_until and async_read used different buffers for reading (asio::streambuf and custom buffer), and some video data consumed by streambuf. Question: how to get video data captured with async_read_until and read rest from tcp buffer?There is is code sample:void read_header(PSample pSample, const boost::system::error_code& error, size_t bytes_transferred){ // Calculate data length with regex boost::asio::const_buffer data = m_headerBuffer.data(); const char* beg = boost::asio::buffer_cast<const char*>(data); const char* end = beg + bytes_transferred; CalculateDataLength(beg, end); // Clear buffer std::vector<char> vec(bytes_transferred); m_headerBuffer.sgetn(&vec[0], bytes_transferred); ReadBody();} Before ReadBody call, i reject streambuf content with sgetn. But i think there ismore data in streambuf that is video data. How can i get it? Below non working sample, but it describe my wishes: // Add before read bodysize_t restBytes = m_headerBuffer.size() - bytes_transferred;if (0 != restBytes){ m_headerBuffer.sgetn(pSample->GetBody(), restBytes);} Then in ReadBody i can to read rest video data with single async_readcall. There is implementation sample: void ReadBody(NMMSS::PSample& pSample){1)//boost::asio::async_read(m_socket, m_headerBuffer.prepare(m_currentSampleLength),2)//boost::asio::async_read_until(m_socket, m_headerBuffer, "\r\n",3)//boost::asio::async_read(m_socket, boost::asio::buffer(pSample->GetBody(), m_currentSampleLength), boost::bind(&CAXISParser::read_body, this, pSample, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));} I trying use 3 variants there:1) Trying read to buffer all video data (dont understand why it doesn't work)2) Very slow variant, as video data is big.3) Preferrable variant P.S. One question more: how can i correctly reject data consumed by streambuf? Now i used the following strategy: streambuf buf; ..... std::vector<char> vec(size); buf.sgetn(&vec[0], size); Is there another strategy for that? For example, commit and consume strategy? I dont need streambuf content in some cases. Best regards, Vadim

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Re: [Boost-users] [bind] Need Help - Function Composition
by loadcom 19 Dec '08

19 Dec '08

Hello Watanabe, Your code works well. And it's much more generic and elegant than the original version. Thank you so much! Best regards Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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boost test + MFC
by Andrew Wan 19 Dec '08

19 Dec '08

Does anyone know how to use boost test library with MFC programs? All the examples & documentation only covers CONSOLE programs. Would be good if there was an MFC example.

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Re: [Boost-users] [boost] tweaking the review process
by David Abrahams 19 Dec '08

19 Dec '08

on Wed Dec 17 2008, Fabio Fracassi <f.fracassi-AT-gmx.net> wrote: > David Abrahams schrieb: >> on Mon Dec 15 2008, John Phillips <phillips-AT-mps.ohio-state.edu> wrote: > [...] >>> I don't know if I was the first to do this, but I have done it. Looking at the >>> current contents of the instructions to review managers, either they have changed >>> since I started managing reviews or I somehow hallucinated extra words to add the > user >>> list to the lists that should receive an announcement of the review. >> >> An announcement is one thing; instructing people to post their reviews >> in the same list is a different thing entirely. >> > > You don't have to, it happens almost automatically if you are not > careful. Many people write their Review as a reply to the original > announcement, and if you are not extra careful to remove the user list > from the recipients your review gets send to both lists. The poster of the announcement should make it clear how to post a review. I never liked the idea of reviews showing up in the list with the subject "Review period for Boost.XXXX begins today" anyway. Also s/he can set the Reply-To: field. -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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Re: [Boost-users] Building the Boost.Test fails
by Gennadiy Rozental 18 Dec '08

18 Dec '08

Maruvekere, Praveen (Contractor) wrote: > Hi Group, > > Any idea what should be the fix for this problem I know that the > template declaration in the class shown below may be problematic What is the version of Boost? What compiler r u using? What r u building? How do you run build? Gennadiy

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[multi_array] Create view at runtime
by loadcom 18 Dec '08

18 Dec '08

Hello, I'm using boost::multi_array of boost 1_36_0 with VS2003SP1. I hope I could determine the number of dimensions of a view of a given multi_array at runtime, or something like this: typedef boost::multi_array<int, 5> array_t; typedef typename array_t::index_range range_t; array_t array; // ... bool f; array_t::array_view<_>::type view = grid[boost::indices[f? range_t() : 11] [f? range_t(1,2): range_t()][rang_t]]; I'll be appreciated to have any kind of help. B/Rgds Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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[Boost.Graph] Accessing edge properties via an edge_iterator
by Julius Ziegler 18 Dec '08

18 Dec '08

Hello list, I wonder what is the fastest method to access edge properties of an adjacency_list when iterating over edges. Actually, the only way I know of for accessing properties is via operator[]: typedef boost::adjacency_list<listS, vecS, boost::directedS, NodeProperty, EdgeProperty > Graph; Graph g; for( tie( ei, ei_end ) = edges( graph ); ei != ei_end; ++ei ) { g[*ei]=something; } From this I conclude, that the right EdgeProperty is stored in some associative container, with edge_descriptor being the key-type. Or does edge_iterator store any information besides a pair<vertex_descriptor, vertex_descriptor>? What is the time complexity of this look_up? To me it feels that there should be a faster way to access properties via an edge_iterator, and by browsing the source I found that edge_iterator has a member function get_property(), however, since it returns void*, and I did not find anything in the documentation, I'm not sure if it is there for this purpose. Thank you very kindly for any hints, Julius

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[bind] Need Help - Function Composition
by loadcom 18 Dec '08

18 Dec '08

Hello all, I'm using boost::bind to get elegant code. Thank the author for the great lib. I'm posting because I ran accross a small problem with the following code. My intention of the code is to find the element of a container with the least abs value of a member (i_). template <typename Arg, typename Result> class less_by_func : public std::binary_function<Arg, Arg, bool> { typedef boost::function<Result(Arg)> fn_t; typedef less_by_func<Arg, Result> self_t; fn_t func_; less_by_func() {} // not open public: less_by_func(const self_t& src) : func_(src.func_) {} explicit less_by_func(const fn_t& func) : func_(func) {} template <typename Arg, typename Result> explicit less_by_func(const less_by_func<Arg, Result>& src) : func_(src.func_) {} bool operator()(const Arg& lhs, const Arg& rhs) const { return func_(lhs) < func_(rhs); } }; // helper function template<typename F> less_by_func<typename F::argument_type, typename F::result_type> make_less_by_func(F func) { return less_by_func<typename F::argument_type, typename F::result_type>(func); } struct A { int i_; A() : i_(0) {} explicit A(int i) : i_(i) {} void set(int i) { i_ = i; } int get() const { return i_; } }; std::vector<A> a_list; a_list.push_back(A(10)); a_list.push_back(A(222)); a_list.push_back(A(-100)); int min_abs = std::min_element(a_list.begin(), a_list.end(), min2max::make_less_by_func( boost::function<int(A)>( boost::bind<int>( std::ptr_fun(&std::abs<int>), boost::bind(&A::i_, _1) ) ) ) )->i_; std::cout << min_abs << std::endl; This code works fine, what I don't understand is why I couldn't remove the explicit construction of a boost::function<int(A)> object and let compiler do the implicit conversion(construction) silently. That means the following code doesn't work: int min_abs = std::min_element(a_list.begin(), a_list.end(), min2max::make_less_by_func( boost::bind<int>( std::ptr_fun(&std::abs<int>), boost::bind(&A::i_, _1) ) ) )->i_; The following code doesn't get compile neither: std::stable_sort(a_list.begin(), a_list.end(), make_less_by_func(boost::bind(&A::i_, _1))); I know a more verbose version like this will also work: int min_abs = std::min_element(a_list.begin(), a_list.end(), boost::bind(std::less(), boost::bind(std::ptr_fun(&std::abs), boost::bind(&A::i_, _1)), boost::bind(std::ptr_fun(&std::abs), boost::bind(&A::i_, _2)) ) )->i_; But I just want the code to be as elegant as possible. :-) My environment is: boost_1_36_0 + VS2003sp1 Thanks for any hints. with best regards Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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[process] How to exec multiple shell commands
by Konstantin Litvinenko 18 Dec '08

18 Dec '08

Hi! I have successfully used boost.process but now stuck with a problem. I need to execute 2 commands in one shell invocation. Both windows and linux allow do that, but I can't figure out how to do it with help of boost.process. Is there interface to do that? PS. I am using old boost.process. I have download process-is-0.4.zip from the vault and didn't find solution for my problem.

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Boost::thread and Dr. Watson
by Francesco Nesci 18 Dec '08

18 Dec '08

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Thread scope
by Birju Prajapati 18 Dec '08

18 Dec '08

Hi, I've seen that when a newly created thread goes out of scope, it keeps running - this suggests to me that they are heap allocated, but can't find anywhere in the documentation that confirms this. Can someone confirm or deny this, and show me where in the docs it is if confirmed? Many thanks, Birju Schneider Trading 4th Floor, 25 Copthall Avenue London EC2R 7BP -------------------------------------------------------- Message from: Birju.Prajapati(a)schneidertrading.com Message to: boost-users(a)lists.boost.org Attached files: 0 This e-mail and any files transmitted with it are confidential, may be legally privileged, and are for the sole use of the intended recipient. Copyright in this e-mail and any accompanying document created by us is owned by us. If you are not the intended recipient of this e-mail or any part of it please telephone our IT Department at the number shown above or by e-mail at info(a)schneidertrading.com. You should not use or disclose to any other person the contents of this e-mail or its attachments (if any), nor take copies. This e-mail is not a representation or warranty and is not intended nor should it be taken to create any legal relations, contractual or otherwise. Schneider Trading Associates Ltd (Registration No. 3692131) is incorporated in England and Wales and the registered office is at 25 Copthall Avenue, London EC2R 7BP. The company is authorised and regulated by the Financial Services Authority

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[boost.tuple] Nested tuples and tie
by Julius Ziegler 18 Dec '08

18 Dec '08

Dear list, is there a way to make constructs like this one work? double a, b, c; tie( tie( a, b ), c ) = make_tuple( make_tuple( 1., 2. ), 3. ); This leads to the first parameter of the "outer" tie getting initialised by the return value of the "inner" tie. That means a temporary gets passed by reference, and the compiler (sort of reasonably) doesnt want to do this. Best regards, Julius

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[bind] Pointer as third parameter
by Jean-Pierre Bergamin 18 Dec '08

18 Dec '08

Dear boost-Users I'm having problems with calling a function that takes a pointer as the third argument through bind. I cannot explain, why the code below does not compile with the function 'op3' enabled. When changing f3 to void f3(int a, int b, int c) { } it also works. I don't see any reasony why this should fail, since f2 also works. Any ideas how to solve this? // --------------------------------------- void f3(int a, int b, int *c) { } void f2(int a, int *b) { } template <typename F> void op3(F f) { int a = 1, b = 2, c = 3; f(a, b, &c); } template <typename F> void op2(F f) { int a = 1, b = 2; f(a, &b); } void call() { op2(boost::bind(&f2, _1, _2)); //op3(boost::bind(&f3, _1, _2, _3)); } // --------------------------------------- This compiles fine. When uncommenting the line op3(...) in the function "call", gcc fails with: test.cpp: In function `void op3(F) [with F = boost::_bi::bind_t<void, void (*)(int, int, int*), boost::_bi::list3<boost::arg<1> (*)(), boost::arg<2> (*)(), boost::arg<3> (*)()> >]': test.cpp:23: instantiated from here test.cpp:11: error: no match for call to `(boost::_bi::bind_t<void, void (*)(int, int, int*), boost::_bi::list3<boost::arg<1> (*)(), boost::arg<2> (*)(), boost::arg<3> (*)()> >) (int&, int&, int*)' /usr/local/include/boost/bind/bind_template.hpp:18: note: candidates are: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()() [with R = void, F = void (*)(int, int, int*), L = boost::_bi::list3<boost::arg<1> (*)(), boost::arg<2> (*)(), boost::arg<3> (*)()>] /usr/local/include/boost/bind/bind_template.hpp:24: note: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()() const [with R = void, F = void (*)(int, int, int*), L = boost::_bi::list3<boost::arg<1> (*)(), boost::arg<2> (*)(), boost::arg<3> (*)()>] /usr/local/include/boost/bind/bind_template.hpp:114: note: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()(A1&, A2&, A3&) [with A1 = int, A2 = int, A3 = int*, R = void, F = void (*)(int, int, int*), L = boost::_bi::list3<boost::arg<1> (*)(), boost::arg<2> (*)(), boost::arg<3> (*)()>] /usr/local/include/boost/bind/bind_template.hpp:120: note: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()(A1&, A2&, A3&) const [with A1 = int, A2 = int, A3 = int*, R = void, F = void (*)(int, int, int*), L = boost::_bi::list3<boost::arg<1> (*)(), boost::arg<2> (*)(), boost::arg<3> (*)()>] MSVC 8 fails with: .\test.cpp(19) : error C2664: 'void boost::_bi::bind_t<R,F,L>::operator ()<int,int,int*__w64 >(A1 &,A2 &,A3 &) const' : cannot convert parameter 3 from 'int *__w64 ' to 'int *__w64 &' with [ R=void, F=void (__cdecl *)(int,int,int *), L=boost::_bi::list3<boost::arg<1>,boost::arg<2>,boost::arg<3>>, A1=int, A2=int, A3=int *__w64 ] .\Sleep.cpp(29) : see reference to function template instantiation 'void op3<boost::_bi::bind_t<R,F,L>>(boost::_bi::bind_t<R,F,L>)' being compiled with [ R=void, F=void (__cdecl *)(int,int,int *), L=boost::_bi::list3<boost::arg<1>,boost::arg<2>,boost::arg<3>> ] Thanks for your help. James

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[?] Looking for something like 'data_grid'
by loadcom 18 Dec '08

18 Dec '08

hello all, Sorry for this probable OT post, but I believe the boost guys must be able to help me. :-) I'm looking for a class similar to this: template class data_grid { //... }; It's a data block of arbitrary dimensions. With it user can do thing's like data look up, and interpolate on any series of specified dimentions, and the like. I guess boost doesn't have an out-of-the-box class like this, while multi_array is close to this requirements. Yes, I could write one by myself. But if there's an existing one, I won't bother to reinvent a wheel. Thanks for any information. with best regards Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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something about UTF8
by wind world 18 Dec '08

18 Dec '08

hi guys, I want to use boost::regex in Windows XP to match Japanese kanji. The encoding of kanji is UTF-8 I want to make sure after I use the funcation: MultibyteToWideChar to change the UTF-8 Kanji string->wstring, I can directly use boost::wregex(from wstring) to match Japanese? Appreciate any help. Worldwind

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[program options] Constraints, missing options
by Georg Sauthoff 18 Dec '08

18 Dec '08

Hi, I am using boost.Program_options and it is quite useful. I miss two features, though. I could not find a way to specify that some option should be mandatory at the command line. Or that some option has to be present at least x times and at most y times at the command line. I mean I can check it myself if the Program_options parser is finished - but I like it better, if the library would do the work for me. In pseudocode I want to write something like this for example: opts.add_options()("file,f", value< vector<string> >() ->min_times(1)->max_times(2), "blah blah"); ./a.out -f foo -f bar # ok ./a.out -f foo -f bar -f bas # exception from the Program_options parser Is this feature missing, or have I overlooked it in the documentation? Another thing I couldn't find: a way to switch program options into a 'checking mode'; i.e. a mode, where the program options code throws an exception if the count of an non existing option is queried (in case of an programming error). For example desc.add_options() ("help,h", "produce help message"); ... vm.set_pedantic(); // <- pseudo code vm.count("foobar"); // <- would throw exception Or even better, if it is possible do register some enum value, which can be used to index into the variables_map - I mean, to get a compile error the option identifier is misspelled (instead of an runtime error ...): enum my_opts { HELP }; desc.addoptions()("help,h", HELP, "produce help message"); vm.count(EHLP); // <- compile error ... Best regards Georg

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submiting boost patches
by Sean Farrow 18 Dec '08

18 Dec '08

Hi: I am currently working on apatch to th bgl in terms of expat. How do I submit this patch when finished? Any help apreciated. Sean

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something about icu
by wind world 17 Dec '08

17 Dec '08

hi guys, I want to use boost::regex in Windows XP + VC6 to match Japanese . I want to know if I need to enable ICU when I compile boost_1_36_0. In my short test program, I did not enable icu and it still can mathch and replace Japanese. But I do not know it is always right. And if I want to match Japanese I mush enable ICU? Appreciate any help. Worldwind

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newbie question on quickbook install
by Christof Warlich 17 Dec '08

17 Dec '08

Hi, I'd like to use quickbook to document my project, but failed to install it on my system (Ubuntu Hardy Heron). When I run bjam --v2 in BOOST_ROOT/tools/quickbook, I get: generate.jam: No such file or directory ../../Jamroot:383: in modules.load *** argument error * rule path.glob ( dirs * : patterns + ) * called with: ( boost/tr1/tr1 : * : bcc32 sun CVS .svn ) * extra argument bcc32 /usr/share/boost-build/util/path.jam:223:see definition of rule 'glob' being called /usr/share/boost-build/build/project.jam:312: in load-jamfile /usr/share/boost-build/build/project.jam:68: in load /usr/share/boost-build/build/project.jam:120: in load-parent /usr/share/boost-build/build/project.jam:447: in initialize /usr/share/boost-build/build/project.jam:301: in load-jamfile /usr/share/boost-build/build/project.jam:68: in load /usr/share/boost-build/build/project.jam:120: in load-parent /usr/share/boost-build/build/project.jam:447: in initialize /usr/share/boost-build/build/project.jam:301: in load-jamfile /usr/share/boost-build/build/project.jam:68: in load /usr/share/boost-build/build/project.jam:170: in project.find /usr/share/boost-build/build-system.jam:148: in load /usr/share/boost-build/kernel/modules.jam:261: in import /usr/share/boost-build/kernel/bootstrap.jam:132: in boost-build /home/christof/work/boost/boost_1_37_0/boost-build.jam:16: in module scope Can anyone help? Thanks, Christof

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Large buffers in boost::asio SSL
by Scott Gifford 17 Dec '08

17 Dec '08

Hello, We're working on a server which will provide service to a large number of mostly idle, low-bandwidth clients. we've use boost::asio as the basis for this, and so far it's working very well. We recently added SSL support, which was very straightforward and seamless. We're starting to look at the scalability of our SSL server, and are seeing some bottlenecks with memory usage. We're seeing about 50KB allocated for each SSL session, even when they are idle. That limits us to somewhat less than 40K users on our box with 2GB of RAM. Our non-SSL version takes about 10KB per user, and we can handle somewhat less than 200K users. Of this 50KB, it looks like 16KB of this is for the OpenSSL BIO object, possibly a bit more with OpenSSL's internal buffers. There is another 16KB buffer stored in the "impl" field of openssl_stream_service. The server is always waiting for data from the clients with an async_read_until, and that also creates a 16KB buffer in its openssl_operation buffer. That gets us up to 48KB of storage for the buffers of each idle connection. So, a few questions. First, does this seem about right? Am I reading the code correctly? Second, it looks like it's harmless to just make these buffers smaller, maybe 1KB, including the BIO buffer. Does that seem reasonable? Can anybody think of a problem with that approach I'm overlooking? I'm certainly no OpenSSL expert, so it's fairly likely... Third, is there a better way to do this? Most of boost::asio uses memory very efficiently, and I wonder if I'm doing something wrong to cause it to allocate all of this memory? Thanks for any thoughts or help! ----Scott.

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lambda code fails to compile on g++ 4.3.1
by Tim Hockin 17 Dec '08

17 Dec '08

This code builds and runs under g++ 4.2.2. It fails under 4.3.1. Help? Tim #include <boost/lambda/lambda.hpp> using boost::lambda::_1; template<typename Tcallback> void function(Tcallback callback) { (void)callback; } int main() { function(_1); // works function(_1+0); // fails return 0; } $ /usr/crosstool/v12/gcc-4.3.1-glibc-2.3.6-grte//i686-unknown-linux-gnu/bin/i686-unknown-linux-gnu-g++ -W -Wall -o broken broken.cc -I/usr/include /usr/include/boost/lambda/detail/lambda_functors.hpp: In instantiation of 'boost::lambda::lambda_functor<boost::lambda::identity<const int> >': /usr/include/boost/lambda/detail/lambda_functor_base.hpp:164: instantiated from 'boost::lambda::detail::deduce_argument_types_<boost::tuples::cons<const int, boost::tuples::null_type>, boost::tuples::null_type>' /usr/include/boost/lambda/detail/lambda_functor_base.hpp:170: instantiated from 'boost::lambda::detail::deduce_argument_types_<boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, boost::tuples::null_type>' /usr/include/boost/lambda/detail/lambda_functor_base.hpp:213: instantiated from 'boost::lambda::detail::deduce_argument_types<boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, boost::tuples::null_type>' /usr/include/boost/lambda/detail/operator_lambda_func_base.hpp:60: instantiated from 'boost::lambda::detail::binary_rt<boost::lambda::arithmetic_action<boost::lambda::plus_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, boost::tuples::null_type>' /usr/include/boost/lambda/detail/operator_lambda_func_base.hpp:206: instantiated from 'boost::lambda::lambda_functor_base<boost::lambda::arithmetic_action<boost::lambda::plus_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >::sig<boost::tuples::null_type>' /usr/include/boost/lambda/detail/lambda_functors.hpp:135: instantiated from 'boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::arithmetic_action<boost::lambda::plus_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >' broken.cc:14: instantiated from here /usr/include/boost/lambda/detail/lambda_functors.hpp:137: warning: type qualifiers ignored on function return type

2 4

boost::interprocess on FreeBSD 7
by Andy Wiese 17 Dec '08

17 Dec '08

My apologies if this is a resend. I think I might have sent the first time before I was approved in the list. Using boost::interprocess from boost_1_37_0 on FreeBSD 7.0, specifically wishing to allocate boost::interprocess::map structures in shared memory pools. I get a segmentation fault in pthread_mutex_lock() from /lib/libthr.so. 3, in a variety of places including anything related to a ShmemAllocator. For example, when I run the example from http://www.boost.org/doc/libs/1_37_0/doc/html/interprocess/allocators_conta… I get the segfault at this line: //Initialize the STL-like allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); I encountered this segfault (always in pthread_mutex_lock) when trying to use mapped file boost::interprocess::map structure that works very well on darwin. Can anyone suggest what I might do to get this working on FreeBSD? Is anyone familiar with FreeBSD 7.0 and the scary inner workings of boost::interprocess interested in a small consulting project? ----------------------------------------------------------------------------------------------- FWIW, here is the complete text of the example, taken verbatim from the tutorial page: void test_ipc2() { using namespace boost::interprocess; shared_memory_object::remove("MySharedMemory"); try{ //A managed shared memory where we can construct objects //associated with a c-string managed_shared_memory segment(create_only, "MySharedMemory", //segment name 65536); //Alias an STL-like allocator of ints that allocates ints from the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator typedef vector<int, ShmemAllocator> MyVector; int initVal[] = {0, 1, 2, 3, 4, 5, 6 }; const int *begVal = initVal; const int *endVal = initVal + sizeof(initVal)/sizeof(initVal[0]); //Initialize the STL-like allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct the vector in the shared memory segment with the STL- like allocator //from a range of iterators MyVector *myvector = segment.construct<MyVector> ("MyVector")/*object name*/ (begVal /*first ctor parameter*/, endVal /*second ctor parameter*/, alloc_inst /*third ctor parameter*/); BOOST_CHECK(myvector); //Use vector as your want std::sort(myvector->rbegin(), myvector->rend()); // . . . //When done, destroy and delete vector from the segment segment.destroy<MyVector>("MyVector"); } catch(...){ shared_memory_object::remove("MySharedMemory"); throw; } shared_memory_object::remove("MySharedMemory"); }

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Re: [Boost-users] [boost] [non Boost] Template troubles.
by David Abrahams 17 Dec '08

17 Dec '08

on Tue Dec 16 2008, Noah Roberts <roberts.noah-AT-gmail.com> wrote: > Robert Jones wrote: >> On Fri, Dec 12, 2008 at 5:52 PM, Noah Roberts <roberts.noah(a)gmail.com>wrote: >> >>> Noah Roberts wrote: >>> >> >> Neil, Noah, Kim - Thanks all for your input. Although no perfect >> solution has emerged it is always good to see a few good minds >> looking at it. > > Don't recall if it was said already but you can also explicitly say > which type you're using: Seriously, this is OT (non-Boost after all), isn't it? As a moderator I overlooked the first few postings, but you should probably take this off the Boost lists now. There are appropriate newsgroups for this sort of thing. Thanks, -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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Re: [Boost-users] [boost] tweaking the review process
by David Abrahams 16 Dec '08

16 Dec '08

on Mon Dec 15 2008, John Phillips <phillips-AT-mps.ohio-state.edu> wrote: > David Abrahams wrote: >> on Fri Nov 21 2008, "Stjepan Rajko" <stjepan.rajko-AT-gmail.com> wrote: >> >>> On Thu, Nov 20, 2008 at 11:40 PM, vicente.botet >>> <vicente.botet(a)wanadoo.fr> wrote: >>>> I would like to make some suggestion to improve the review management: >>>> >>> Thank you for starting this discussion. >>> >>>> * I had notice only at the end of the the review that the review tokes place on > two >>> mailing lists (devel ans user). Maybe this is usaual on Boost reviews but I was not >>> aware. It will be more transaparent if all the reviews were posted to the same > mailing >>> list, maybe a specific one should be created. >>> >>> Yes, this is a bit of an issue. I mentioned that both lists are used >>> in my post that opened the review (in my notes to first-time >>> reviewers) to try to give people a heads-up (but... I often get >>> long-winded and I'm sure it's easy to miss parts of my posts :-)). >>> >>> Having a dedicated, or at least recommended mailing list (either dev >>> or user) might be a good thing. >> >> It has always been the -devel list, at least up until recently. How >> reviews began being posted to -users, I do not know. >> > > I don't know if I was the first to do this, but I have done it. Looking at the > current contents of the instructions to review managers, either they have changed > since I started managing reviews or I somehow hallucinated extra words to add the user > list to the lists that should receive an announcement of the review. An announcement is one thing; instructing people to post their reviews in the same list is a different thing entirely. -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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can't extend boost::any on windows
by Michael Linck 16 Dec '08

16 Dec '08

Hi, I've implemented a simple, low level json formatting utility to complement tinyjson's lightweight parser. To do this, I've extended boost::any only to add a "format()" function to it that is aware of what types the content can take in a json structure and produces the appropriate string. The default constructor and the constructor with a value are the only things I implemented, aside from the format function. Both just call the base constructor. Compiled in gcc, everything works fabulously. Apparently, a functioning assignment operator and copy constructor are appropriately inherited and everything runs great. On windows, however, some subtle difference causes assignment and copies to seg-fault. The real problem is that, for the life of me, I can't find a way to implement assignment or copies explicitly, that doesn't also bomb out. I can probably come up with a work around that stores my type in shared pointers so they're never actually copied, but I'm really curious if anyone could explain what causes this. Here are some code snippets to illustrate the behavior: void test(){ std::cout<<"messing around with boost any"<<std::endl; boost::any tAny; boost::any tStringAny(std::string("some string")); tAny = tStringAny; std::cout<<"string any assignable to any"<<std::endl; std::cout<<"messing around with value type"<<std::endl; sysshep::json::Value tValue; std::cout<<"formatted blank value "<<tValue.format()<<std::endl; std::cout<<"making string value"<<std::endl; sysshep::json::Value tStringValue(std::string("some_string")); std::cout<<"formatted string value "<<tStringValue.format()<<std::endl; std::cout<<"assigning string value to blank value"<<std::endl; tValue = tStringValue; /// FAILS std::cout<<"formatted blank value after assignment"<<tValue.format()<<std::endl; } class Value : public boost::any { public: Value():boost::any(){}; template<typename ValueTypeTA> Value(const ValueTypeTA & aValue): : boost::any(aValue) {} virtual ~Value(); std::string format() const; }; I'm not going to list the different ways I've attempted to implement copy and assignment, some more plausible than others, out of respect for brevity. If you try a build on windows, VC8, you should be able to mess around with this to your hearts content. It's really annoying because it was a factor in the fundamental elegance of the parsing implementation, because I see no reason why it shouldn't work, because it worked fine in linux, and because it put my windows port at least a day behind customer expectations. thanks for any insight.

3 3

issues when compiling graph library with expat
by Sean Farrow 16 Dec '08

16 Dec '08

Hi: When compiling the graph library with expat to add graph ml, the libraries fails to compile, I've declared environment variables EXPAT_INCLUDE and EXPAT_LIBRARY but it's failing expat.h even though the directory is in the pat as "c:\program files\expat\source\lib\" Any help apreciated. Sean.

3 5

CRC - error: shift count is too large
by Mike Dalgity 16 Dec '08

16 Dec '08

Hi, I'm attempting to get the Boost CRC to compile for a TI C6713 DSP. I'm using C6000 Code Gen Tools 6.1.6 which is based on EDG. STL implementation is from Dinkumware. When I include <boost/crc.hpp> I get the following errors: "C:/Program Files/boost_1_37_0/boost/crc.hpp", line 286: error: shift count is too large detected during instantiation of class "boost::detail::high_uint_t<Bits> [with Bits=64U]" at line 433 "C:/Program Files/boost_1_37_0/boost/crc.hpp", line 288: error: shift count is too large detected during instantiation of class "boost::detail::high_uint_t<Bits> [with Bits=64U]" at line 433 I'm new to Boost so I could use some help figuring this out. I looked at crc.hpp and high_uint_t appears to be a structure containing two uint_t types corresponding with the errors. In integer.hpp the uint_t struct does not evaluate long long. On this architecture a long is 48 bits and long long is 64 bits. I've only included the header so why is it trying to instantiate a 64 bit type? Thanks, Mike

1 1

[xpressive] Overlapping match results?
by Dave Jenkins 16 Dec '08

16 Dec '08

Is there a way to get overlapping match results from Xpressive? For example, when searching for "aa" in the string "aaaa", I want three results [as]as, a[aa]a, and aa[aa]. Currently, I'm only getting the two non-overlapping results [aa]aa and aa[aa]. I tried the regex 'a' >> before('a'). That almost gave me what I wanted (three results with the correct positions). The problem is that the lengths are wrong. What I need are lengths that include the before() characters. Is that possible? I know in this simple example I could just add 1 to the lengths, but I'm looking for overlapping results on more complex regexes. Thanks, Dave Jenkins

2 2

boost compile to arm
by leslie lige 16 Dec '08

16 Dec '08

Hi, I'm tring to cross compile boost 1.37 to arm, I found that I need to add "__arm__" definition to get compile correctly, but I don't know where do I define __arm__ macro will be global to all. Defautly, the arch is defined as __i386__ when I do cross compile with arm toolchain. regards, Leslie _________________________________________________________________ Explore the seven wonders of the world http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE

2 3

building regex with icu
by Sean Farrow 16 Dec '08

16 Dec '08

Hi: what aditional command line switches/parameters do I need to add to bjam to build regex with icu? Chers Sean.

4 3

this_thread::sleep + undefined reference?
by John D 16 Dec '08

16 Dec '08

Hello This will be an exceptionally stupid problem for whomever is kind enough to clarify a cause and solution. I will keep it brief in hopes that it is not an issue in need of complexity. The code: boost::this_thread::sleep(boost::posix_time::milliseconds(20)); The attempt: g++ -lcurl -lboost_thread -lpthread -pthread c.cpp -o app /tmp/cc2YRa76.o: In function `void boost::this_thread::sleep<boost::date_time::subsecond_duration<boost::posix_time::time_duration, 1000ll> >(boost::date_time::subsecond_duration<boost::posix_time::time_duration, 1000ll> const&)': c.cpp:(.text._ZN5boost11this_thread5sleepINS_9date_time18subsecond_durationINS_10posix_time13time_durationELx1000EEEEEvRKT_[void boost::this_thread::sleep<boost::date_time::subsecond_duration<boost::posix_time::time_duration, 1000ll> >(boost::date_time::subsecond_duration<boost::posix_time::time_duration, 1000ll> const&)]+0x50): undefined reference to `boost::this_thread::sleep(boost::posix_time::ptime const&)' collect2: ld returned 1 exit status I will post more code if need be, but even general guidance will likely lead me to a solution. Thanks John

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Re: [Boost-users] [boost] tweaking the review process
by David Abrahams 16 Dec '08

16 Dec '08

on Fri Nov 21 2008, John Phillips <phillips-AT-mps.ohio-state.edu> wrote: > Stjepan Rajko wrote: >> On Fri, Nov 21, 2008 at 10:52 AM, John Phillips >> <phillips(a)mps.ohio-state.edu> wrote: >>> Stjepan Rajko wrote: >>>> [snip] >>> Do you think it would help if the Wizards stressed this need and requested >>> an affirmation of it as part of the lead in to the review? >>> >> >> Definitely. I'm not sure whether stressing this requirement would >> turn off potential review managers because of the added effort, but I >> think it would make the overall review process better. >> >> Stjepan > > > I don't want to discourage anyone who will do a good job of managing a review, but > if we decide this is a necessary step in providing a good review then I'm not upset by > discouraging anyone who won't do it. I'm not sure just what's being proposed here (so this might be off-base), but it's important not to make anything unnecessarily burdensome. We need to rely on peoples' intelligence and sense of responsibility without making egregious rules. For example, a review manager should not -- in general -- need to do a comprehensive review herself; she has enough on her plate already. 95% of the time it should be enough to make a judgement based on the other reviews: both their votes and their quality, depth, etc. At the end of the review period, if she is truly left unsure whether the library should be accepted, a review manager might go through the process herself, but otherwise a comprehensive review from the manager should not be required. I think it would be good if the review wizards could make it clear that they are available to provide guidance in case review managers have questions about how to do their jobs well. -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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tweaking the review process (was: signals2 review results)
by Stjepan Rajko 16 Dec '08

16 Dec '08

On Thu, Nov 20, 2008 at 11:40 PM, vicente.botet <vicente.botet(a)wanadoo.fr> wrote: > > I would like to make some suggestion to improve the review management: > Thank you for starting this discussion. > * I had notice only at the end of the the review that the review tokes place on two mailing lists (devel ans user). Maybe this is usaual on Boost reviews but I was not aware. It will be more transaparent if all the reviews were posted to the same mailing list, maybe a specific one should be created. Yes, this is a bit of an issue. I mentioned that both lists are used in my post that opened the review (in my notes to first-time reviewers) to try to give people a heads-up (but... I often get long-winded and I'm sure it's easy to miss parts of my posts :-)). Having a dedicated, or at least recommended mailing list (either dev or user) might be a good thing. The only problem I see regarding a completely separate mailing list is that it requires active effort to sign-up for and follow. I think that for many people (even those that are genuinely interested in the library), the fact that the review is happening at time X-Y very easily slips off the radar. Having the e-mails constantly appear in the common lists also serves to remind everyone of the ongoing review, and I suspect it leads to many valuable impromptu comments and even full reviews from people that perhaps weren't originally planning on participating in the review, but end up following the review because it happens on the list (I recall being in this situation myself several times). > > * From the 5 committing reviewers making this review possible only 3 made a review and 2 of them late. I'm wondering if this new rule must be preserved as the review can be accepted without the commiting reviewers review. Trying to use committed reviewers was a new thing for this review (it was proposed by others in http://tinyurl.com/48tdjs) Now that it has been tried out, it would be good to reflect on how things went. For the reviews that were late, the reviewers were very diligently contacting me about their changing time constraints and offered times that would work for them, and I found those times acceptable. Out of the two committed reviewers that did not submit, one also diligently worked with me on setting up an alternative timeline, but in the end contacted me saying that a full review would not be possible after all, and offered a brief report of looking into the library and a brief rationale for acceptance (as the points matched those of other reviewers, I didn't forward it to the list). I was not able to contact the final reviewer after a certain point. I think the major benefit of the committed reviewers is the high probability that they actually will submit a review. Things always happen, and boost contributions are all volunteer time, but I found that overall the committed reviewers *very responsibly* succeeded in keeping their commitment as well as they could. Were they not committed reviewers, I suspect many of them would have considered giving up. In addition, the extensions that the committed reviewers negotiated gave other reviewers a chance to contribute. So, I feel that committed reviews are a good way of reasonably making sure that a certain number of reviews will be submitted. I'm not sure that the library acceptance / rejection should be influenced by the number of committed reviews (reviews from others are a perfectly good substitute). While we're on this topic... The one thing that the number of committed reviewers should definitely influence is whether the review happens in the first place. We were fortunate to get 5 people sign up, which was the only threshold proposed, so we followed through with the review. I was wondering what to do if the threshold wasn't crossed, and I think what I would have proposed is some sort of a holding pattern, where the review schedule page is updated to say something like "signals2 - reviewers needed, contact review manager to sign up as a reviewer". Once the threshold is crossed, the reviewers, manager and author can schedule a time. Another thing... many of the committed reviewers reported that they were first time reviewers (and the reviews they submitted were impressively detailed and very valuable). Personally, I was thrilled by this, since getting new participation in boost is critical to sustaining its quality . Perhaps some combination of allowing reviewers to commit beforehand, and explicitly encouraging reviews focused on the user perspective (another suggestion from the http://tinyurl.com/48tdjs thread), helped in getting first-time reviewers (perhaps the reviewers can comment on this?). > > * There were some reviews that came into this list by the intermediation of the review manager with a delay between the posting of the reviwer and forward from the RM. One negative review posted the 4th and reveived in this list the 11th other positive posted the 2nd and received in this list 3rd. I think that the review manager should not encourage the reviewers to send the reviews to himself. This will avoid this kind of delays. So I purpose that only the reviews sent to this single mailing list must be taken in account. Yes, this particular delay is entirely my fault. I can't explain why I didn't notice this email until so late (which is the point where I contacted the poster notifying him I would like to forward the mail, and forwarded it the following morning). Allowing reviews to be sent to the review manager is straight from http://www.boost.org/community/reviews.html (Introduction paragraph). There are two valid reasons for this, IMO: * the reviewer is only subscribed to one of {boost, boost-user, boost-announce} lists, and would like the reviewer to be forwarded to both boost and boost-user lists (if there was a dedicated review list, like you suggest, that was also open to all posters, then this reason would go away) * the reviewer would like to remain anonymous to the list (granted, this could also be accomplished by sending from an anonymous e-mail). If this stays as it is, the RM should be more diligent about monitoring her personal mail, which I apparently wasn't. > > * Even if the review was over the 10th there were 2 accepting reviews comming from the commiting reviewers just some hours before the review result annoncement 19th. I think that the review manager must state clearly when the review is over and do not accept any review after. This do not means that the RMcannot change this date, but annnce it clearly. I tried to keep my timeline as transparent as possible. In my review-closing email, I asked people to let me know if they were considering writing a review. Those that contacted me were informed of the timeline of pending reviews. When the last promised review was submitted, I set a hard deadline. Given the uncertainty in people's schedules, I decided to approach this in a flexible way. That was just my personal preference - I'm sure setting a hard deadline earlier would have been a fine choice as well. > > I hope this will help to improve future reviews, > Thanks again for starting this discussion and for your suggestions - I also hope good improvements will come out of it. Stjepan

3 2

building boost (regex) in mingw
by Lorenzo Bettini 15 Dec '08

15 Dec '08

Hi I'm trying to install boost regex library under mingw but I can't seem to succeed... the simple configure way does not work I've also tried bjam --build-dir=./tmp --toolset=gcc stage --with-regex but this does not create .a .so files, but only .lib files that I cannot use with mingw compiler... any help please? thanks in advance Lorenzo

1 0

Lite serialization lib optimized for performance
by Sebastian.Karlsson＠mmorpgs.org 15 Dec '08

15 Dec '08

Hi, I've created a small serialization library which takes a lot of inspiration from the great works of Robert Ramey. The main difference is that my implementation has favoured performance and file size while trying to maintain most of the goodies of boost::serialization. The largest thing missing, I believe, is pointer tracking. I'd like to make it available both for review and others in case there's any interest for such a library, but know of no good public place to make it available. // Sebastian Karlsson

2 3

Re: [Boost-users] Fast XML Parser
by Alan M. Carroll 15 Dec '08

15 Dec '08

That's only nicer if you have a use for XPath. That is one reason I wouldn't recommend rapidXML in use cases where the application is doing non-trivial edits of the DOM tree, because that's the kind of situation in which XPath is useful. But if your application consumes all the XML every time and writes the entire DOM tree every time, then XPath is of no utility. It's in some sense unfortunate, but the bottom line is that there isn't "the best" XML library, only more or less appropriate ones for particular use cases. I suspect this is a big contributor to the lack of XML support from Boost. At 05:38 AM 12/15/2008, Jose wrote: >Yes, rapidXML is quite nice. It was inspired by pugixml >http://code.google.com/p/pugixml/, which is even nicer becaue it >provides an xpath support. >I personally find rapidXML not as useful/nice without xpath support. >It's also quite easy to migrate from either one library to the other

1 0

BoostCon 2009: Call for Participation
by Hartmut Kaiser 15 Dec '08

15 Dec '08

Hi all, before we all relax into the holidays I wanted to remind you all about next year's Boost Conference in Aspen, CO, USA, May 3-9. Even if all important dates are listed in the attached Call for Participation, I'll list them here once again: Proposals for submissions due: January 10th 2009. Proposals acceptances sent (tentative program available): February 10th, 2009 Fully scheduled program available: March 1st, 2009 Session materials due: April 1st 2009. IOW, you might want to use some of your free time during the next weeks to think about a possible contribution. It really doesn't take much time to come up with a short abstract! Let's make sure BoostCon 2009 will be a major C++ event! Happy holidays! Regards Hartmut Program Committee Chair BoostCon 2009

3 4

Buffering and ASIO
by Vadim Shmelev 15 Dec '08

15 Dec '08

Good day. I'm trying to read video data transferred by HTTP. I use the following function in order to read HTTP header: boost::asio::async_read_until(m_socket, m_headerBuffer, "\r\n\r\n", boost::bind(&CAXISParser::read_header, this, boost::asio::placeholders::error,boost::asio::placeholders::bytes_transferred)); , where m_headerBuffer is asio::streambuf object. During header parsing i can get video sample length. Now I want to read all video data in one function call, for example: boost::asio::async_read(m_socket, boost::asio::buffer(pSample->GetBody(), m_currentSampleLength),boost::bind(&CAXISParser::read_body, this, pSample, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); , where pSample is object with buffer for video data. There is problem that async_read_until captures some data from video data, and that call's behavior is incorrect. How can i fight that problem? For example, how can i figure out number of bytes left in streambuf and copy them to my buffer, and then read rest with async_read? I'm will very appreciate for any advices. Thanks in advance, Vadim

2 2

Fast XML Parser
by Jeff Dunlap 15 Dec '08

15 Dec '08

I've been looking at a bunch of C++ libraries for parsing XML and RapidXML looks very interesting to me. They have some very impressive benchmarks on their site due to it being a in-situ parser: http://rapidxml.sourceforge.net/ (way faster than most other XML parsers). I think that this is something that can be most useful for many of us. I know that existing boost libs can get this done but probably more complex than an exclusive lib for XML parsing. Anyway, I cannot find samples anywhere and I am not experienced enough to know how to use the lib. This is working code that I have so far (important comments include): #include "../test_utils.hpp" #include "../../rapidxml.hpp" #include "../../rapidxml_utils.hpp" #include "../../rapidxml_print.hpp" #include <string> #include <vector> #include <fstream> #include <stdexcept> #include <cstring> #include <sstream> using namespace std; void test() { char xml[] = "<?xml version=\"1.0\" encoding=\"latin-1\"?>" "<book>" "</book>"; //Parse the original document rapidxml::xml_document<> doc; // character type defaults to char doc.parse<0>(xml); // 0 means default parse flags // doc object is now a root of DOM tree containing representation of the parsed XML. // Because all RapidXml interface is contained inside namespace rapidxml, users must either bring contents of this namespace into scope, or fully qualify all the names. // Class xml_document represents a root of the DOM hierarchy. By means of public inheritance, it is also an xml_node and a memory_pool. // Template parameter of xml_document::parse() function is used to specify parsing flags, with which you can fine-tune behaviour of the parser. // Note that flags must be a compile-time constant. // To access the DOM tree, use methods of xml_node and xml_attribute classes: std::cout << "Name of my first node is: " << doc.first_node()->name() << "\n"; // Name of my first node is: book // This works but is less descriptive than 'Create proper node type' below //rapidxml::xml_node<> *node; // Create proper node type rapidxml::xml_node<char> *node = 0; node = doc.allocate_node(/*rapidxml::node_declaration*/ rapidxml::node_element, "author", "John Doe"); doc.first_node()->append_node(node); node = doc.allocate_node(rapidxml::node_element, "author", "Jane Doe"); doc.first_node()->append_node(node); node = doc.allocate_node(rapidxml::node_element, "author", "Bob Doe"); doc.first_node()->append_node(node); std::stringstream ss; ss << *doc.first_node(); std::string result_xml = ss.str(); std::cout <<result_xml<<std::endl; } int main() { test(); return 0; } I just don't have the skill to figure out how to use this. If anyone can provide some beginner snippets on how to use this library, it would be much appreciated. Idiot proof snippets on how to add, edit, delete with comments would be awsome. Thank you -- ELKNews FREE Edition - Empower your News Reader! http://www.atozedsoftware.com

4 5

linking error while using Boost-regex and Stlport in the same project
by ashish 15 Dec '08

15 Dec '08

> Hi, I'm working on a project which needs both boost-regex, and STLPORT. When these two libraries are used individually for some sample examples, they work fine. But when used both in the same project, I get linking errors as follows: >______________________________________________________________________ main/main.cpp:6: instantiated from here /home/kpendyal/software/STLport-5.1.5/stlport/stl/_algobase.c:374: warning: unused parameter '__comp2' /usr/bin/ld: warning: libstdc++.so.5, needed by /home/kpendyal/software/xerces-c_2_8_0/lib/libxerces-c.so, may conflict with libstdc++.so.6 main/main.o(.gnu.linkonce.t._ZN5boost9re_detail12perl_matcherIPKcN8stlp_ std9allocatorINS_9sub_matchIS3_EEEENS_12regex_traitsIcNS_16cpp_regex_ traitsIcEEEEE11match_matchEv+0xa3): In function `boost::re_detail::perl_matcher<char const*, stlp_std::allocator<boost::sub_match<char const*> >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::match_match()': : undefined reference to `boost::match_results<char const*, stlp_std::allocator<boost::sub_match<char const*> > >::maybe_assign(boost::match_results<char const*, stlp_std::allocator<boost::sub_match<char const*> > > const&)' main/main.o(.gnu.linkonce.t._ZN5boost12regex_searchIPKcN8stlp_ std9allocatorINS_9sub_matchIS2_EEEEcNS_12regex_traitsIcNS_16cpp_ regex_traitsIcEEEEEEbT_SC_RNS_13match_resultsISC_T0_EERKNS_11basic_ regexIT1_T2_EENS_15regex_constants12_match_flagsESC_+0x8e): In function `bool boost::regex_search<char const*, stlp_std::allocator<boost::sub_match<char const*> >, char, boost::regex_traits<char, boost::cpp_regex_ traits<char> > >(char const*, char const*, boost::match_results<char const*, stlp_std::allocator<boost::sub_match<char const*> > >&, boost::basic_ regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags, char const*)': : undefined reference to `boost::re_detail::perl_matcher<char const*, stlp_std::allocator<boost::sub_match<char const*> >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::construct_init(boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags)' main/main.o(.gnu.linkonce.t._ZN5boost9re_detail11raise_errorINS_ 20regex_traits_wrapperINS_12regex_traitsIcNS_16cpp_regex_ traitsIcEEEEEEEEvRKT_NS_15regex_constants10error_typeE+0xa3): In function `void boost::re_detail::raise_error<boost::regex_traits_wrapper<boost::regex_ traits<char, boost::cpp_regex_traits<char> > > >(boost::regex_traits_wrapper<boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::error _type)': : undefined reference to `boost::re_detail::raise_runtime_error(stlp_std::runtime _error const&)' main/main.o(.gnu.linkonce.t._ZN5boost9re_detail18basic_regex _parserIcNS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEE4failENS_ 15regex_constants10error_typeEi+0x108): In function `boost::re_detail::basic_regex_parser<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::fail(boost::regex_constants::error_type, int)': : undefined reference to `boost::regex_error::regex_error(stlp_std::basic_string<char, stlp_std::char_traits<char>, stlp_std::allocator<char> > const&, boost::regex_constants::error_type, int)' collect2: ld returned 1 exit status make: *** [ctoolkit] Error 1 ______________________________________________________________________ > > I tried to build boost with STLPORT, but never could get the library with '-p' in it's name, which I suppose is required here. How can I get it, or is there some other way???? Please help asap... >

4 8

[thread] targetting win32 in cygwin/mingw
by JOAQUIN M. LOPEZ MUÑOZ 15 Dec '08

15 Dec '08

Hi, We're having some problems in the Boost testing lists setting up a mingw environment to target Win32 when building Boost.Thread, please see the thread starting at: http://lists.boost.org/boost-testing/2008/12/6068.php Is there any documented (or undocumented) way to do this? We've been playing with DBOOST_THREAD_WIN32 and BOOST_HAS_WINTHREADS to no avail. Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

2 1

Meaning of or_<> with empty arguments
by Reetesh Mukul 15 Dec '08

15 Dec '08

Hi, This code compiles:- #include <boost/mpl/or.hpp> using boost::mpl; int main() { typedef boost::mpl::or_<> A; A a; } What is the meaning an empty or_<> ? On my gcc compiler I can see that there is no type/value inside A. With Regards, Reetesh Mukul

2 3

[Regex] problems compiling with gcc 4.4
by Aonghus Lawlor 14 Dec '08

14 Dec '08

Hi, I am using boost 1.37 on osx from macports and I have a problem using the regex library with gcc 4.4, although it seems to work perfectly with gcc 4.3 and 4.2. The problem is with creating a boost::regex object- simple program below: #include <boost/regex.hpp> #include <string> int main(int argc, char **argv) { std::string s("(.*)bar|(.*)bah"); boost::regex re_node(s); return 1; } The backtrace it produces is below: (gdb) bt #0 0x90d90b9e in __kill () #1 0x90d90b91 in kill$UNIX2003 () #2 0x90e07ec2 in raise () #3 0x90e1747f in abort () #4 0x0026792c in __gnu_cxx::__verbose_terminate_handler () #5 0x00265239 in __cxxabiv1::__terminate () #6 0x0026527d in std::terminate () #7 0x0026539c in __cxa_throw () #8 0x001eeb00 in std::__throw_bad_cast () #9 0x00370d25 in std::use_facet<std::messages<char> > () #10 0x00127c93 in boost::re_detail::cpp_regex_traits_base<char>::imbue () at cpp_regex_traits.hpp:215 #11 regex_data [inlined] () at basic_regex.hpp:173 #12 basic_regex_implementation (this=0x500200) at cpp_regex_traits.hpp:93 #13 0x001256a6 in shared_ptr<boost::re_detail::basic_regex_implementation<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > > [inlined] () at shared_ptr.hpp:525 #14 boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign (this=0xbfffe790, p1=0x5001ec "(.*)bar|(.*)bah", p2=0x5001fb "", f=0) at basic_regex.hpp:525 #15 0x00001d6a in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign () #16 0x00001d3e in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign<std::char_traits<char>, std::allocator<char> > () #17 0x00001c9f in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::basic_regex<std::char_traits<char>, std::allocator<char> > () #18 0x00001b20 in main () (gdb) Is this a problem with boost, or with the compiler? Any ideas for a fix? many thanks, a

3 5

Re: [Boost-users] [boost] [review][constrained_value] compile-time lambdas
by Gordon Woodhull 14 Dec '08

14 Dec '08

>> I guess we have to wait for decltype to be able to use lambda >> expressions as predicates here? > > Why? There are already examples with lambda predicates in the docs. Yes, constrained_value does support lambdas at runtime using runtime boost::function. I was hoping that we will also be possible to specify lambdas at compile time, which is more efficient because boost::function incurs cost equivalent to a virtual method call (it prohibits inlining and dereferences a pointer). And there is the cost of storing the function pointer too... I am imagining things like constrained_value<int, decltype(_1>0 && ! bind(isnan,_1))>. In my perfect imaginary world this would be a zero-size predicate which is default constructable because it carries no data. Thus the expression doesn't need to be duplicated on construction and is stored entirely in the constrained_value typedef. 0 might have to be construct<mpl::integral_c<0> >() :-D I'm sure there are 1000 things wrong with this, just fantasizing... I guess this also falls into the bin of "what's the perfect predicate library?"

3 2

Confused with Lambda library usage
by QPlace 14 Dec '08

14 Dec '08

Cannot figure out how to properly use lambda library in following situation (pseudo-code below): class Unit { }; class Test { public: void dosmth(Unit* unit) {} }; int main() { vector<Unit*> lst; Test t; for_each (lst.begin(), lst.end(), ?// I want to call t.dosmth with each Unit* in list } Any help will be greatly appreciated.

3 5

Sobol generator
by Laurent GIORELLO 13 Dec '08

13 Dec '08

Hi all, In GSL, we can find an implementation for the sobol distribution (quasi monte carlo). Maybe we could insert this into Boost. Cheers, Laurent

1 0

Normal distribution
by Laurent GIORELLO 13 Dec '08

13 Dec '08

Hi all, I've read the implementation for the normal distribution and I've seen people wanted Box-Muller algorithm. Instead, I suggest Marsaglia method. Instead of using cos and sin, we use a square soot. The advantage is that we already use the square root for the log. Then it's really faster. Anybody for this ? Laurent

1 0

Abstract factory
by Jason Felice 13 Dec '08

13 Dec '08

Does boost have an abstract factory? I'm reading through Alexandrescu's "Modern C++ Design" and finding the idea neat, and I'm surprised to not find an equivalent in boost. Or alternately, is there another preferred solution?

3 3

thread_group / removal of items
by Christian Ost 13 Dec '08

13 Dec '08

Hi, I have a question concerning the removal from entries of a thread_group. Consider the following code (i am working on a small threaded server): in TCPServer.h: boost::thread_group threads in TCPServer.cpp: int TCPServer::loop(int listen_fd) { for (;;) { [connect client] boost::thread* thrd = new boost::thread(boost::bind(&TCPServer::readMessages, this, rfd)); threads.add_thread(thrd); } } } int TCPServer::readMessages(int rfd) { boost::this_thread::at_thread_exit(boost::bind(&TCPServer::exitThread, this)); for(;;) { [read message] if ([buffer is empty]) { [close connection] return(0); } } return 1; } void TCPServer::exitThread() { cout << "thread exited" << endl; } Now I would like to remove the exited thread from the thread_group, however to do this I would need its thread* object - but the maximum of information I can get from boost::this_thread is a boost::thread::id and I haven't found a possibility to get a thread by its thread::id so far. How can/should I solve this issue? I would be quite happy about any advice... Thank you very much! Christian

3 2

seeking comments on 'weak_key_map' experiments
by Nicolas Lelong 13 Dec '08

13 Dec '08

Hello, I've been doing too much Python recently - thanks to boost.python - and my return in the c++ world in quite painful. To help me manage some of my objects lifetime dependencies, I wanted an access to a system similar to the Python WeakKeyDictionary class : Mapping class that references keys weakly. Entries in the dictionary will be > discarded when there is no longer a strong reference to the key. This can be > used to associate additional data with an object owned by other parts of an > application without adding attributes to those objects. I drafted a small 'weak_key_map' class based on boost weak_ptr, shared_ptr deleters, and a base class enabling classes to be used as keys in the weak_key_map. A small use case example is shown after, and source of weak_key_map & co are attached. I was wandering if someone had experience to share about a similar system ? For a first draft, it already serves me well - but, I'm not very happy with to "pollute" keys with the base class 'enable_master_ptr'... Any idea to improve all this ? Best regards, Nicolas. int Master_count = 0; class Master : public mgd::enable_master_ptr<Master> { public: Master() { Master_count++; } ~Master() { Master_count--; } }; int Dependent_count = 0; class Dependent : boost::noncopyable { public: Dependent() { Dependent_count++; } ~Dependent() { Dependent_count--; } }; BOOST_AUTO_TEST_CASE( test_weak_key_map_lifeTime ) { typedef boost::shared_ptr<Dependent> value_t; typedef mgd::weak_key_map<Master, value_t> map_t; map_t map; { Master master1; BOOST_CHECK( !map[&master1] ); map[&master1] = value_t( new Dependent ); BOOST_CHECK( map[&master1] ); { Master master2; map[&master2] = value_t( new Dependent ); BOOST_REQUIRE_EQUAL( Master_count, 2 ); BOOST_REQUIRE_EQUAL( Dependent_count, 2 ); } map[&master1] = value_t( new Dependent ); BOOST_REQUIRE_EQUAL( Master_count, 1 ); BOOST_REQUIRE_EQUAL( Dependent_count, 1 ); map.clear(); BOOST_REQUIRE_EQUAL( Master_count, 1 ); BOOST_REQUIRE_EQUAL( Dependent_count, 0 ); } BOOST_REQUIRE_EQUAL( Master_count, 0 ); BOOST_REQUIRE_EQUAL( Dependent_count, 0 ); }

4 6

Need advice on std::queue syncronization using boost::mutex - maybe a bug in pthread?
by Ilya Kalujny 13 Dec '08

13 Dec '08

Hello All! I`d like to ask for your kind advice regarding boost::mutex behaviour. I dont see what i`m doing wrong here. The issue is that at some point a mutex used to syncronize access to std::queue becomes locked on it's own, despite being explicitly unlocked before. I can repeat this more or less consistently. I triple checked the logic behind code and it seems correct to me. Here is the code and some explanations (i build and test under windows): Class itself: #pragma once #include <queue> // simple std::queue based boost::mutex syncronized queue template <typename T> class SyncedQueue : boost::noncopyable { private: std::queue<T> queue; // this is intended to be locked when queue is empty boost::mutex emptyIndicator; //this is intended to be locked when queue is being modified boost::mutex accessGuard; public: SyncedQueue(const SyncedQueue<T> &) { //no copy constructor since we got mutexes } SyncedQueue() { // Queue is empty at start emptyIndicator.lock(); } bool push ( T object ) { accessGuard.lock(); queue.push(object); // if someone has been waiting for data to become available in queue - let them go on emptyIndicator.unlock(); accessGuard.unlock(); return true; } bool pop ( T& object ) { // See if data is available, wait to aquire lock otherwise emptyIndicator.lock(); // OK, somethings in the queue now, we can go on accessGuard.lock(); object = queue.front(); queue.pop(); // If there is anything left in the queue - release emptyIndicator to notify other poppers that they can go on if (queue.size() > 0) { emptyIndicator.unlock(); } accessGuard.unlock(); return true; } }; Here is the test Code: #include "stdafx.h" #include <string> #include <iostream> #include <boost/thread.hpp> #include <boost/shared_ptr.hpp> #include <include/threadpool.hpp> #include "SyncedQueue.h" // global variable for the queue SyncedQueue< boost::shared_ptr < std::string > > syncedQueue; void testWriteQueue() { for (int i = 0; i < 100; i++) { char szBuff[128]; boost::shared_ptr< std::string > msgPtr; std::string tmpString = "Message"; tmpString += itoa(i,szBuff, 10); msgPtr.reset(new std::string(tmpString)); syncedQueue.push(msgPtr); std::cout << "Sent " << msgPtr->c_str() << std::endl; } // After this thread completes, reader thread sometimes deadlocks! std::cout << "Sent all" << std::endl; } void testReadQueue() { int recievedmessnum = 0; while(recievedmessnum != 100) { boost::shared_ptr< std::string > recievedMsgPtr; // After this writer thread completes, it sometimes sometimes deadlocks trying to aqurie emptyIndicator! syncedQueue.pop(recievedMsgPtr); std::cout << "Recieved " << recievedMsgPtr->c_str() << std::endl; recievedmessnum++; } std::cout << "Recieved all" << std::endl; } int main(int argc, char** argv) { using namespace boost::threadpool; pool tp(2); tp.schedule(&testWriteQueue); tp.schedule(&testReadQueue); tp.wait(); std::cout << "Test complete" << std::endl; } Thanks in advance, Ilya.

2 2

[non Boost] Template troubles.
by Robert Jones 12 Dec '08

12 Dec '08

Ok, first off, this is not explicitly about Boost, which I know is against the Boost guidelines, but I hope you'll all forgive me. Indirectly it is through trying to use Boost that i've bumped into this. A little code snippet... #include <cstddef> template < typename T, std :: size_t sz > struct Block { typedef T type[ sz ][ sz ]; }; template < typename T > void assign( T & assignee, const T & value ); template < typename T, std :: size_t sz > void assign( T ( & assignee )[ sz ], const T ( & value )[ sz ] ); int main( ) { Block< int, 16 > :: type a; const Block< int, 16 > :: type b = { }; assign( a, b ); } This compiles under Gcc & Comeau, but MS VisStudio reckons the call to assign in main is ambiguous. Any thoughts? Also, if I put all the template declarations in an anonymous namespace, Comeau fails to compile, while Gcc is still ok! Have we encountered this before, and is there a known work around? Thanks. - Rob.

3 6

Thread and exception
by Janne Kätevä 12 Dec '08

12 Dec '08

Hi I have noticed that on Ubuntu my code that uses Boost Threads works fine when I throw exceptions (for example strings) and catch them in the same thread. But this doesn't seem to work on Windows XP with Mingw gcc 3.4.5. If I throw a exception in thread, the program crashes. Is there some known problem with Boost Thread and Mingw? I'm using Boost 1.37. Simple example: #include <exception> #include <boost/thread/thread.hpp> using namespace std; class callable { public: void run() { try { cout << "Throwing" << endl; throw string("error"); } catch(string &e) { cout << "Error: " << e << endl; } } void operator()() { this->run(); } }; int main() { callable c; boost::thread thrd(boost::ref(c)); thrd.join(); return 0; } Janne

2 1

handle different endian
by boost001 12 Dec '08

12 Dec '08

Does Boost have method to do endian swap, like those ntohl and htonl? -- View this message in context: http://www.nabble.com/handle-different-endian-tp20979512p20979512.html Sent from the Boost - Users mailing list archive at Nabble.com.

2 1

[program_options] word-wrapping broken in presence of default arguments
by Peter Simons 12 Dec '08

12 Dec '08

Hi, in Boost 1.37.0, this program #include <iostream> #include <string> #include <boost/program_options.hpp> int main(int argc, char * argv[]) { using namespace std; using namespace boost::program_options; options_description cmdline_options("Supported options"); cmdline_options.add_options() ("help", "this is a sufficiently long text to require word-wrapping") ("prefix", value<string>()->default_value("/h/proj/tmp/dispatch"), "root path of the dispatch installation") ; cerr << cmdline_options << endl; return 0; } displays a usage message that looks weird: $ g++ foo.cpp -lboost_program_options.a && ./a.out | Supported options: | --help this is a sufficiently long text to requ | ire word-wrapping | --prefix arg (=/h/proj/tmp/dispatch) root path of the dispatch installation It appears that the word-wrapping algorithm can't handle the default argument properly. Is that a known problem? Can I work around that somehow? I also wonder whether it's possible to format the help string such that it's printed in the *next line*, like this: | --prefix arg (=/ridiculously/long/path/that/leaves/no/room/on/right/side) | root path of the dispatch installation I tried adding a '\n' at the beginning of the help string, but that didn't have the desired effect. Is there any way to accomplish this? Take care, Peter

1 0

[Serialization] Confusing problem serializing a vector of pointers to a base class
by Martin Weinberg 12 Dec '08

12 Dec '08

I'm struggling debugging a problem with recent versions >1.35. I have a huge code with a boost-serializaton-based persistence system. In short, all "persistent" classes derive from a base class. The code keeps track of the instances by a vector to pointers to the base class. Starting with version 1.36, saving the archive results in the following run-time message: /usr/local/boost_1_37_0/include/boost-1_37/boost/archive/impl/archive_pointer_oserializer.ipp:64: static const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::archive_pointer_oserializer<Archive>::find(const boost::serialization::extended_type_info&) [with Archive = boost::archive::polymorphic_oarchive]: Assertion `it != boost::serialization::singleton< oserializer_map<Archive> >::get_const_instance().end()' failed. I would be good, I know, to post a snippet that produces the error. Unfortunately, I've tried unsuccessfully for some time to make this occur in a simple test code with similar features to the main code. Can someone give me any pointers that would help me debug this? After a >3 days of struggle, I'm at a loss. Again, there are no problems with 1.35. I'm not suggesting that the error is not of my own making but maybe this is a clue. TIA!

1 0

The "error C2668" on VC6
by wind world 12 Dec '08

12 Dec '08

Hi guys, I'm trying to introduce the boost regex into my old VC6 project. "using namespace std" is declearared in many files. When I include "#include <boost/regex.hpp>", I receive the following error: error C2668: 'memset' : ambiguous call to overloaded function. When I remove "using namespace std" or add :: to memset(memset -> ::memset), it can be ok. I want to ask wheather there is the third way to solve this problem. Appreciate any help. Worldwind

2 1

Proto: extending the example mixed.cpp
by Kim Kuen Tang 11 Dec '08

11 Dec '08

Hi all, i wnat to extend the example in the file mixed.cpp with an operator[]: double operator []( std::ptrdiff_t i ) const { DereferenceCtx const deref = {}; AdvanceCtx adctx(i); //just shift the iterator with std::advance typename boost::result_of<Begin(Expr const &)>::type expr2 = Begin()(*this); proto::eval(expr2,adctx); return proto::eval(expr2, deref); } This works well. However is it possible to let proto figure out what the result_type of this function is? I've tried to program in this way. typedef typename boost::result_of<Begin(Expr const &)>::type Expr2; typedef typename proto::result_of::eval<Expr,DereferenceCtx>::type result_type; result_type operator []( std::ptrdiff_t i ) const { DereferenceCtx const deref = {}; AdvanceCtx adctx(i); Expr2 expr2 = Begin()(*this); proto::eval(expr2,adctx); return proto::eval(expr2, deref); } But the compiler complained that the nested struct eval in the struct struct DereferenceCtx { template<typename Expr, typename EnableIf = void> struct eval : proto::default_eval<Expr, DereferenceCtx const> {}; cannot be instantiated by this particulat template. So I guess I ' ve to write a grammar for this issue. Is this true?

2 1

[BGL] Matrix as Graph - Graph Adaptor
by Liao, Elizabeth 11 Dec '08

11 Dec '08

Hi, I'm looking at using the Graph Adaptor class for Matrices but I'm not sure how to use it. Specifically, I'm confused by the macro BOOST_GRAPH_ADAPT_MATRIX_TO_GRAPH in matrix_as_graph.cpp. Does anyone have an example on how to use it? I'm more at the evaluation stage on whether to use BGL or not so I'm not familiar with other BGL functions. Any help would be appreciated. Thanks! Liz

2 1

More on: Problem solved: LNK2019 with boost::thread_group [!]
by Joseph A. Marks 11 Dec '08

11 Dec '08

Thanks, Steve, I get this in thread form so your great reply isn't included here. (AMDG). We often (though not always) have the following line also: using boost::unit_test_framework::test_suite; My coding standards manual says only to put using directives in .cpp files rather than .h (or .hpp) files. Joseph A. Marks PHONE: 612-788-9658 e-mail: josephamarks(a)yahoo.com --- On Thu, 12/11/08, Joseph A. Marks <josephamarks(a)yahoo.com> wrote: > In case anyone ever needs to know, here are the steps taken > to solve the problem: {NOTE: A colleague helped me with > this}. > > Re-loaded Boost, upgrading to v. 1.37 {this upgrade may be > a red herring, but it didn't hurt). This version is > very friendly to compiling in MS VS 2008 (version 9). > > Then, added the following, at the top of any relevant file: > > #include <boost/test/floating_point_comparison.hpp> > > #define BOOST_TEST_MAIN "Test > put_your_town_string_here" > #include <boost/test/unit_test.hpp> > #include <boost/test/auto_unit_test.hpp> > > I am not sure if the first of these includes is required, > but this always seems to work. > > Hopefully, someone will be helped by this e-mail at some > point or other. > > Thanks, > Sincerely, > > Joseph A. Marks > e-mail: josephamarks(a)yahoo.com > > > --- On Mon, 12/8/08, Joseph A. Marks > <josephamarks(a)yahoo.com> wrote: > > > From: Joseph A. Marks <josephamarks(a)yahoo.com> > > Subject: LNK2019 with boost::thread_group [!] > > To: boost-devel(a)lists.boost.org > > Date: Monday, December 8, 2008, 10:53 AM > > I get the following linker error using Boost, I am > trying to > > get it to compile using VS 2008, with a makefile > system: > > > > error LNK2019: unresolved external symbol "class > > boost::unit_test::test_suite * __cdecl > > init_unit_test_suite(int,char * * const)" > > > (?init_unit_test_suite@@YAPAVtest_suite@unit_test@boost@@HQAPAD@Z) > > referenced in function _main > > > > Does anyone have any insight? > > > > Thanks in advance, > > > > Joseph A. Marks > > e-mail: josephamarks @ yahoo.com > > Joseph A. Marks > e-mail: josephamarks(a)yahoo.com Joseph A. Marks PHONE: 612-788-9658 e-mail: josephamarks(a)yahoo.com

2 1

maybe ot: debugger expression evaluators
by Noah Roberts 11 Dec '08

11 Dec '08

Does anyone know of any set of VS evaluators ( http://msdn.microsoft.com/en-us/library/8fwk67y3(VS.80).aspx ) that would make debugging code that uses some of the more internally complex boost constructs a bit easier? Ones I can think of that would make life easier: whatever is returned by bind smart pointers (not so bad right now actually) boost::function others? For instance, with the bind it would be nice to see simply the address of the function and an array of the arguments...with some obviously being displayed as "placeholder". The boost::function one could maybe just show the function object it stores. Currently, to get to this information you have to weed through quite a few levels of abstraction. Not saying this is bad, it's obviously necessary, but it can make debugging through these objects a bit of a hassle.

2 1

Re: [Boost-users] signals/slots and boost::functions
by david.weber＠l-3com.com 11 Dec '08

11 Dec '08

For those interested, It appears the reason was because of a compiler error I hit, and didn't ask about, or really worry how to resolve it. :-/ Function declaration: typedef boost::function < VSSP ( std::string, EncodingEnum) > CreateTypeFunc; bool ElementBase::disconnectCreateTypeSignal(const CreateTypeFunc& slot) { LOG4CXX_DEBUG(logger_, "disconnectCreateTypeSignal in"); bool retValue = false; createTypeSignal_.disconnect(slot); <snip!> } Error: (apologies for the length) c:\Program Files\boost\boost_1_35_0\boost\signals\signal_template.hpp(242) : error C2666: 'boost::operator`=='' : 4 over loads have similar conversions; c:\Program Files\boost\boost_1_35_0\boost\function\function_base.hpp(669): could be 'boo st::enable_if_c<B,T>::type boost::operator ==<boost::signal2<R,T1,T2,Combiner,Group,GroupCompare,SlotFunction>::slo t_fun ction_type>(Functor,const boost::function_base &) with [B=true,T=bool,R=boost::detail::function_traits_helper<boost::add _pointer<boost::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::result_type,T 1=boost::detail::function_traits_helper<boost::add_pointer<boost::shared _ptr<model::VariantStorage> (std::string,model:: EncodingEnum::EncodingEnum)>::type>::arg1_type,T2=boost::detail::functio n_traits_helper<boost::add_pointer<boost::shared _ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::arg2_type,Combi ner=boost::last_valu e<boost::detail::function_traits_helper<boost::add_pointer<boost::shared _ptr<model::VariantStorage> (std::string,model:: EncodingEnum::EncodingEnum)>::type>::result_type>,Group=int,GroupCompare =std::less<int>,SlotFunction=boost::function<mod el::VariantStorageSharedPtr (std::string,model::EncodingEnum::EncodingEnum)>,Functor=boost::signal2< boost::detail::funct ion_traits_helper<boost::add_pointer<boost::shared_ptr<model::VariantSto rage> (std::string,model::EncodingEnum::Encoding Enum)>::type>::result_type,boost::detail::function_traits_helper<boost:: add_pointer<boost::shared_ptr<model::VariantStor age> (std::string,model::EncodingEnum::EncodingEnum)>::type>::arg1_type,boost ::detail::function_traits_helper<boost::add _pointer<boost::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::arg2_type,boo st::last_value<boost::detail::function_traits_helper<boost::add_pointer< boost::shared_ptr<model::VariantStorage> (std::s tring,model::EncodingEnum::EncodingEnum)>::type>::result_type>,int,std:: less<int>,boost::function<model::VariantStorageS haredPtr (std::string,model::EncodingEnum::EncodingEnum)>>::slot_function_type]'; c:\Program Files\boost\boost_1_35_0\bo ost\function\function_base.hpp(660): or 'boost::enable_if_c<B,T>::type boost::operator ==<Function>(const boost::f unction_base &,Functor) with [B=true,T=bool,Function=model::ElementBase::CreateTypeFunc,Functor=model ::ElementBase::Crea teTypeFunc]'; c:\Program Files\boost\boost_1_35_0\boost\function\function_template.hpp(832): or 'void boost::opera tor ==<R,T0,T1,Allocator>(const boost::function2<R,T0,T1,Allocator> &,const boost::function2<R,T0,T1,Allocator> &) with [R=model::VariantStorageSharedPtr,T0=std::string,T1=model::EncodingEnum: :EncodingEnum,Allocator=std::allocator<void>]'; or 'built-in C++ operator==(boost::function2<R,T0,T1,Allocator>::safe_bool with [R=model::VariantStorageSharedPtr, T0=std::string,T1=model::EncodingEnum::EncodingEnum,Allocator=std::alloc ator<void>], boost::function2<R,T0,T1,Allocator> ::safe_bool with [R=model::VariantStorageSharedPtr,T0=std::string,T1=model::EncodingEnum: :EncodingEnum,Allocator=std::al locator<void>])'; while trying to match the argument list '(boost::signal2<R,T1,T2,Combiner,Group,GroupCompare,SlotFunct ion>::slot_function_type with [R=boost::detail::function_traits_helper<boost::add_pointer<boost::share d_ptr<model::Varia ntStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::result_type,T1= boost::detail::function_traits_helper <boost::add_pointer<boost::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::ar g1_type,T2=boost::detail::function_traits_helper<boost::add_pointer<boos t::shared_ptr<model::VariantStorage> (std::strin g,model::EncodingEnum::EncodingEnum)>::type>::arg2_type,Combiner=boost:: last_value<boost::detail::function_traits_helper <boost::add_pointer<boost::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::re sult_type>,Group=int,GroupCompare=std::less<int>,SlotFunction=boost::fun ction<model::VariantStorageSharedPtr (std::strin g,model::EncodingEnum::EncodingEnum)>], const model::ElementBase::CreateTypeFunc)'; c:\Program Files\boost\boost_1_35_0\ boost\signals\signal_template.hpp(224) : see reference to function template instantiation 'void boost::signal2<R,T1,T2,C ombiner,Group,GroupCompare,SlotFunction>::do_disconnect<T>(const Function &,boost::mpl::bool_<C_>) with [R=boost::detail ::function_traits_helper<boost::add_pointer<boost::shared_ptr<model::Var iantStorage> (std::string,model::EncodingEnum::E ncodingEnum)>::type>::result_type,T1=boost::detail::function_traits_help er<boost::add_pointer<boost::shared_ptr<model::V ariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::arg1_type,T2=bo ost::detail::function_traits_help er<boost::add_pointer<boost::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>:: arg2_type,Combiner=boost::last_value<boost::detail::function_traits_help er<boost::add_pointer<boost::shared_ptr<model::V ariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::result_type>,Gr oup=int,GroupCompare=std::less<in t>,SlotFunction=boost::function<model::VariantStorageSharedPtr (std::string,model::EncodingEnum::EncodingEnum)>,T=model: :ElementBase::CreateTypeFunc,Function=model::ElementBase::CreateTypeFunc ,C_=false]' being compiled; c:\Documents and Set tings\td26134\Desktop\trunk1\src\model\ElementBase.cpp(440) : see reference to function template instantiation 'void boo st::signal2<R,T1,T2,Combiner,Group,GroupCompare,SlotFunction>::disconnec t<model::ElementBase::CreateTypeFunc>(const T &) with [R=boost::detail::function_traits_helper<boost::add_pointer<boost::share d_ptr<model::VariantStorage> (std::string, model::EncodingEnum::EncodingEnum)>::type>::result_type,T1=boost::detail ::function_traits_helper<boost::add_pointer<boos t::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::arg1_type,T2=bo ost::detail ::function_traits_helper<boost::add_pointer<boost::shared_ptr<model::Var iantStorage> (std::string,model::EncodingEnum::E ncodingEnum)>::type>::arg2_type,Combiner=boost::last_value<boost::detail ::function_traits_helper<boost::add_pointer<boos t::shared_ptr<model::VariantStorage> (std::string,model::EncodingEnum::EncodingEnum)>::type>::result_type>,Gr oup=int,Gro upCompare=std::less<int>,SlotFunction=boost::function<model::VariantStor ageSharedPtr (std::string,model::EncodingEnum::E ncodingEnum)>,T=model::ElementBase::CreateTypeFunc]' being compiled scons: *** [build_dir\Windows\src-model\ElementBase.obj] Error 2

2 3

Problem solved: LNK2019 with boost::thread_group [!]
by Joseph A. Marks 11 Dec '08

11 Dec '08

Problem solved: In case anyone ever needs to know, here are the steps taken to solve the problem: {NOTE: A colleague helped me with this}. Re-loaded Boost, upgrading to v. 1.37 {this upgrade may be a red herring, but it didn't hurt). This version is very friendly to compiling in MS VS 2008 (version 9). Then, added the following, at the top of any relevant file: #include <boost/test/floating_point_comparison.hpp> #define BOOST_TEST_MAIN "Test put_your_town_string_here" #include <boost/test/unit_test.hpp> #include <boost/test/auto_unit_test.hpp> I am not sure if the first of these includes is required, but this always seems to work. Hopefully, someone will be helped by this e-mail at some point or other. Thanks, Sincerely, Joseph A. Marks e-mail: josephamarks(a)yahoo.com --- On Mon, 12/8/08, Joseph A. Marks <josephamarks(a)yahoo.com> wrote: > From: Joseph A. Marks <josephamarks(a)yahoo.com> > Subject: LNK2019 with boost::thread_group [!] > To: boost-devel(a)lists.boost.org > Date: Monday, December 8, 2008, 10:53 AM > I get the following linker error using Boost, I am trying to > get it to compile using VS 2008, with a makefile system: > > error LNK2019: unresolved external symbol "class > boost::unit_test::test_suite * __cdecl > init_unit_test_suite(int,char * * const)" > (?init_unit_test_suite@@YAPAVtest_suite@unit_test@boost@@HQAPAD@Z) > referenced in function _main > > Does anyone have any insight? > > Thanks in advance, > > Joseph A. Marks > e-mail: josephamarks @ yahoo.com Joseph A. Marks e-mail: josephamarks(a)yahoo.com

2 1

Boost + __stdcall calling convention
by cdongieux.ext＠orange-ftgroup.com 11 Dec '08

11 Dec '08

Hello, I am currently programming a dll in COM format with Visual Studio 2005. For it to be in COM format, the calling convention has to be __stdcall. In my project, I need somme Boost code, just to get my life easier :) My problem is that the compiler complains in linking process : I have unresolved Boost symbols whereas I included the good .lib. I tried many workarounds, and I saw that when I change the calling convention to __cdecl, the project compiles fine. Unfortunatly I can't register the DLL with regsvr32 since the format is not correct. Is it possible to use Boost libraries with the __stdcall convention ? Do you have an idea/solution ? Thanks in advance.

3 2

[spirit] real_p fails on negative exponent
by Jan Boehme 11 Dec '08

11 Dec '08

Hi, on my system (RHEL3, libc 2.3.2, gcc 3.2.3, Intel 10.1 which is used to compile and link) real_p fails to parse real numbers like 1.0E-001 and it is most likely the negative exponent as 1.0E001 works as expected. Our investigations brought us to numerics.hpp line 162 where the int parser which is used by real_p is declared as 'int_parser<T, 10, 1, -1>' with T=double. I don't see the reason for this yet and the 'out of the box' int parser 'int_p' itself is declared using 'int_parser<int>'. Here my questions: Do I have to expect any problems using int instead double for the real_p exp_n parser? Is this a kind of a mistake as even int_p is declared using 'int'? Thank you very much for your support, Jan. p.s.: Yes, I know gcc 3.2.3 isn't officially supported by boost but please consider helping me even so, thanks.

4 9

Re: [Boost-users] [boost] [review][constrained_value] Review of ConstrainedValueLibrary begins today
by Jesse Perla 11 Dec '08

11 Dec '08

Robert: >Yes, this might be added in the future to the library itself. But first I want >to become confident this is what actually users need and that this solution is >general enough. Therefore, I'd be grateful if you (and other possible users) >could test the provided code and say how well is it fulfilling the requirements. Absolutely. I will test around the beginning of the year. >I think the best solution for dynamic constraints union (or intersection) is to >use boost::signal, and this is how I would implement this. Again, this is a >possible addition to the library in the future if it proves generally needed. Yes, the signals approach would solve multiple constraint bounds-checking through a predicate. But it doesn't solve my main use case: Querying the sub-type information associated with a type for numeric algorithms, which may not be connected intervals. For my code (and I would guess most people's) numeric applications, I will turn off bounds-checking when running in release, and manually trigger inclusion testing as I see necessary. But the type information will be perfectly efficient at runtime for generating grids, checking convergence of optimizers, etc. The reason that I think you need to think through the unions sooner rather than later is that there is a chance it could change your design to have the library return statically available type data as lists/iterators. And it is worth thinking if you want to generalize the interval concept sooner rather than later. If it is possible and there is no future-proofing necessary, then that is fine. >On numerics: >I have no experience with such computations and no code like you describe to >test. However, I'll be grateful for any reports from users after trying to use >the library in such applications. Yup. I write code some test cases when I get started. >On numeric_limits: >Then you may specialise those functions for constrained -- I think it's a better >solution than providing numeric_limits for constrained in the library. I hear what you are saying. Yu can't write your own numeric_limits classes/functions... they are very platform specific and are part of the standard. Though there may be ways to subclass from your super-type. If it is possible to automatically subclass the numeric limits from the underlying type it would really make writing generic code for numerics much easier. If not automatically, then perhaps we could just have a usage pattern where you declare the constrained type, then the numeric_limits through inheritance? This is also related to the testing of this library with existing numerics libraries. Some of these (mine for example) are relying on numeric_limits existing for whatever type is passed in to the function. So there is a good chance that some numeric libraries would fail without this, and it would be a major disincentive for people to using this library. Thanks Robert, I will get back in contact early January to see how I can help after the review has died down. -Jesse

2 1

Re: [Boost-users] [boost] [review][constrained_value] Review ofConstrainedValueLibrary begins today
by Jesse Perla 10 Dec '08

10 Dec '08

>This too is already solved if any predicate is acceptable: just use a >predicate functor that forwards via a pointer or reference to another >global predicate. Or (somewhat less efficient but easier) use the >dynamic boost::function predicate that is already included and >boost::bind/lambda/phoenix to a method on this global object. Gordon: I absolutely agree that if this library was purely for bounds testing, managing invariants, etc, that predicates are sufficient. But for high performance numerics, that is not what would happen. First of all, you would turn off automatic testing at runtime. But one of the key value of this library, in both release/debug, for those examples is to get information about the bounds and intervals from the type itself for generic algorithms. A predicate as a function can test assignment, but it can't give back structured data for these algorithms. If you can show me how the testing predicate can be easily queried within this framework for the type metadata itself(e.g. a list of intervals), then I will shut up. I really think people need to think through this alternative use case of this powerful library. And Robert: There are a lot of discussions on the boost mailing list (which I can't post on) about NaN and others for numeric_limits. In virtually every case with high performance computing, you would turn off predicate testing on assignment for release builds because it is too expensive. Then you would, judiciously, test inclusion of the value. So the model here is that if bounded_float is a subset of float, a value in this class it is always in the float superset, but I can test inclusion within the other subset that I have defined. Here, predicates work fine as long as there is a manual way to test set inclusion. And numeric libraries frequently use NaN, infinity, etc. as signals for algorithms. So these values should be associated with the superset in the model as a default approach. So what I am saying is that people should be given the option (as a preprocessor instruction is sufficient) to have the value as always within the bounds vs. considering this as a "set" which they can then test inclusion at their own liesure. This is a pragmatic approach to ensure consistency of this library with existing generic numerical algorithms, which is just as important for the numerics as solving the floating point problem. Also, I am not aware of the structure of the numeric_limits, but I doubt these are written to be virtual/subclassed due to efficiency. What this means is that you would probably have to write your own traits class if we don't make this automatic, and you can't pick or choose to override existing tratis. And these numeric traits are impossible for normal developers to write since they are platform specific. Last, and this is not something I know enough about because I am not a numeric analyst, but the epsilon method discussed in the mailing list may have a flaw for numeric work. What we effectively are doing here is creating an epsilon neighborhood for testing equality. As we know from set theory/topology, this does not create a weak ordering because it fails transitivity. Now, one might say that this is irrelevant because it is a reasonable approximation for pragmatic reasons, but you run into a problem in numerics. The reason is that many numerical algorithms are already testing within an epsilon neighborhood for convergence of algorithms, derivatives, etc. So we need to be REALLY careful that this epsilon ball is well within those balls, or we may seriously mess up algorithms depending on a comparison operator.... This may or may not be a problem, but I would pose it on the boost list to ensure that people are thinking about it. One solution may be to rely on the numeric_limits::epsilon trait that would always be available, would be platform specific, and I believe is the small possible neighborhood of a point. Whether this is the maximum amount of truncation possible, I do not know. -Jesse

3 2

signals/slots and boost::functions
by david.weber＠l-3com.com 10 Dec '08

10 Dec '08

I have a class, where I want callers to be able to register/deregister signals/slots. They will pass in a function pointer, and we'll hook it up to the signal, and manage the connection object. Part of the management, is I need to map the function pointer to the actual connection object. This is where the trouble comes in. Since a boost::function doesn't have an operator <, the simplest way is to just map it to an unsigned long long, and store the raw address of the underlying function. So, my connect function: typedef VSSP (*TargetType) ( std::string, EncodingEnum); typedef boost::function < VSSP ( std::string, EncodingEnum) > CreateTypeFunc; bool ElementBase::connectCreateTypeSignal(const CreateTypeFunc& slot) { LOG4CXX_DEBUG(logger_, "connectCreateTypeSignal in"); bool retValue = false; unsigned long long slotAddr = (unsigned long long)slot.target< TargetType >(); LOG4CXX_DEBUG(logger_, "*** slotAddr = " + (boost::format("%08X") % slotAddr).str()); <snip> } One of my checks, is to ensure that you don't connect the same thing multiple times. So, I have a test case that does this, and expects it to bomb out: VSSP getTypeSlot(std::string fqn, EncodingEnum encoding) { <snip> return VSSP; } BOOST_FIXTURE_TEST_CASE(ElementBase_connectCreateType, ElementBaseTestFixture) { BOOST_CHECK(true == ebp->connectCreateTypeSignal(getTypeSlot)); BOOST_CHECK(false == ebp->connectCreateTypeSignal(getTypeSlot)); } My debug printouts, are shoing unexpected behavior. The address that I am getting from target is different every time it is called, even though I'm calling with the same function (getTypeSlot). I would expect this if I was getting the address of the function object, because I'm creating one implicitly through the call, but not dereferencing via target(), unless I'm misunderstanding what target() does. I just need the stupid address of the function passed in. Help!! TIA --dw

3 5

Eigenvalues
by r89 10 Dec '08

10 Dec '08

Hi, It seems like Boost doesn't support eigen-analysis, is that true? I've been using VXL/VNL for eigenanalysis, but my project must get rid of dependencies on VXL/VNL, so I'm wondering what would be the easiest transition? By the way, the matrices I'm dealing with are of size 2x2 and 3x3. Thanks! -- View this message in context: http://www.nabble.com/Eigenvalues-tp20941764p20941764.html Sent from the Boost - Users mailing list archive at Nabble.com.

4 3

[BGL] passing a graph from one function to another
by r89 10 Dec '08

10 Dec '08

Hi all, I have a graph defined as follows (the same as in the Dijkstra shortest path example code): typedef adjacency_list < listS, vecS, directedS, no_property, property < edge_weight_t, float > > graph_t; The following works fine: graph_t myGraph(array, edge_array + num_arcs, weights, num_nodes); However, now I want to do the above line inside a function (say, fun_A), and I want another function (say, fun_B) to have access to "myGraph". How should I do that? I wish I could do something like this: graph_t myGraph; fun_A(graph_t &myGraph) { myGraph(array, edge_array + num_arcs, weights, num_nodes); } fun_B(graph_t &myGraph) { // using myGraph to run some graph algorithm... } but it doesn't work. Any suggestions? Thanks! -- View this message in context: http://www.nabble.com/-BGL--passing-a-graph-from-one-function-to-another-tp… Sent from the Boost - Users mailing list archive at Nabble.com.

5 12

[bind/lambda] Matching signature constness?
by Robert Jones 10 Dec '08

10 Dec '08

Here's a bit of code (and my apologies for it's length, but I'm unsure which bit is the failure point) #include <cstddef> #include "boost/lambda/lambda.hpp" #include "boost/lambda/bind.hpp" #include "boost/function.hpp" #include "boost/type_traits.hpp" namespace { template < bool > struct cmp_detail { template < typename T > static bool cmp( const T & lhs, const T & rhs ) { return lhs != rhs; } }; template < > struct cmp_detail< true > { template < typename T, std :: size_t sz > static bool cmp( const T ( & lhs )[ sz ], const T ( & rhs )[ sz ] ) { using boost :: lambda :: _1; using boost :: lambda :: bind; using boost :: lambda :: var; boost :: function< bool( unsigned ) > cmp_element = bind( cmp_detail< boost :: is_array< T > :: value > :: cmp, var( lhs )[ _1 ], var( rhs )[ _1 ] ); for ( unsigned i = 0; i != sz; ++ i ) if ( cmp_element( i ) ) // if ( cmp_detail< boost :: is_array< T > :: value > :: cmp( lhs[ i ], rhs[ i ] ) ) return true; return false; } }; template < typename T > bool cmp( const T & lhs, const T & rhs ) { return cmp_detail< boost :: is_array< T > :: value > :: cmp( lhs, rhs ); } template < typename T, std :: size_t sz > struct Block { typedef T type[ sz ][ sz ]; }; } int main( ) { Block< int, 16 > :: type a; Block< int, 16 > :: type b; cmp( a, b ); } The problem is the bind call in cmp_detail<true>::cmp(...). Error is this block.cpp: In static member function `static bool <unnamed>::cmp_detail< true>::cmp(const T (&)[sz], const T (&)[sz]) [w ith T = int[16], unsigned int sz = 16u]': block.cpp:45: instantiated from `bool <unnamed>::cmp(const T&, const T&) [with T = int[16][16]]' block.cpp:61: instantiated from here block.cpp:32: error: no matching function for call to `bind(<unknown type>, const boost::lambda::lambda_functor<boost::l ambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::subscript_action>, boost::tuples::tuple<boost::lam bda::lambda_functor<boost::lambda::identity<const int (&)[16][16]> >, boost::lambda::lambda_functor<boost::lambda::place holder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boo st::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, const boost::l ambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::subscript_action>, b oost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::identity<const int (&)[16][16]> >, boost::lambda::lambd a_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples:: null_type> > >)' I think perhaps the var() calls are not preserving constness quite right? Any help would be welcome. Thanks. - Rob.

2 3

[Review] UUID library (mini-)review starts today, November 23rd
by Hartmut Kaiser 10 Dec '08

10 Dec '08

Hi all, The mini-review of Andy Tompkins UUID library starts today, November 23rd 2008, and will end on November 30th. I really hope to see your vote and your participation in the discussions on the Boost mailing lists! The library can be downloaded from the vault here (it's the file uuid_v13.zip in the topmost directory): http://tinyurl.com/6xx28b The initial review of the UUID library ended with a provisional acceptance (read here: http://article.gmane.org/gmane.comp.lib.boost.user/27774/) This mini review is meant to allow for a final decision after looking at the changed parts of the library. Here is a list of things fixed and changed: - fixed the licensing issues revealed by the initial review - fixed the security vulnerability revealed by the initial review - renamed to uuid, moved all classes, functions, etc. to namespace boost::uuids - implemented sha1 hash function (thus no license problem) - new class basic_uuid_generator to create random-based uuids. The random number generator is no longer hard coded. It can use any random number generator, default is boost::mt19937 - implemented a good seed function for random number generators - all functions are now reentrant, all classes are as thread safe as an int and the library is no longer dependent on Boost.Thread --------------------------------------------------- Please always state in your review, whether you think the library should be accepted as a Boost library! Additionally please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Regards Hartmut Review Manager

14 39

Dplicate emails
by Richard Howells 10 Dec '08

10 Dec '08

Since a couple days back I seem to be getting every email twice. It is coincident with me repaving my computer, but it does NOT happen to my individual emails nor to my other mailing list subscriptions. Is it just me? Cheers, Richard richard(a)dynamisys.co.uk www.dynamisys.co.uk L: (+44) (0)1793 731225 M: (+44) (0)7732 971786

2 1

[boost.build] multiple definitions of symbols at link since revision 49800.
by Nigel Dyer 10 Dec '08

10 Dec '08

Hello I am using the trunk release of boost, and started having problems with multiple definitions of symbols during linking (see example linker output below). I can cure the problem by removing the change to tools\build\v2\build\generators.jam introduced in revision 49800. It only seems to occur if the following headers: #include <boost/test/floating_point_comparison.hpp> #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> are included in precompiled headers which are included in cpp files that are created by the antlr parser generator. It occurs on a compilation with darwin, but not msvc. It is unclear whether the generator.jam change has identified a waekness in the boost libraries, or there is a problem with the revision 49800 change that only surfaces in obscure circumstances, or the change has highlighted a problem in my code. It can be fixed by removing the includes from the precompiled header. I feel this should not be necessary As a boost newbie it is unclear whether I should I change my code or raise a bug report. I would be grateful for suggestions. Nigel Example linker failures. /usr/libexec/gcc/i686-apple-darwin8/4.0.1/ld: multiple definitions of symbol boost::test_tools::(anonymous namespace)::check_is_close /Volumes/RAID1/xraid/data/bifa/Dev/Projects/Bio/bin/Bio/darwin-4.0.1/release/link-static/libbio.a(BiobaseLexer.o) definition of boost::test_tools::(anonymous namespace)::check_is_close in section (__DATA,__const) /Volumes/RAID1/xraid/data/bifa/Dev/Projects/Bio/bin/Bio/darwin-4.0.1/release/link-static/libbio.a(ArrayLexer.o) definition of boost::test_tools::(anonymous namespace)::check_is_close in section (__DATA,__const)

4 3

[BGL] iterator/descriptor invalidation
by Julius Ziegler 10 Dec '08

10 Dec '08

Dear list, the documentation of adjacency_list states, that a call to add_vertex() does not invalidate any iterators nor descriptors. However, following code segfaults, because retrieving vertex descriptors from an edge_iterator via source() and target() does not work (example should compile as is): #include <iostream> #include <boost/graph/adjacency_list.hpp> using namespace boost; typedef adjacency_list<listS, vecS, directedS > Graph; int main() { Graph g(3); add_edge( 0, 1, g ); add_edge( 1, 2, g ); add_edge( 2, 0, g ); Graph::edge_iterator ei, ei_end; for( tie( ei, ei_end ) = edges( g ); ei != ei_end; ++ei ) { std::cout << source( *ei, g ) << " " << target( *ei, g ) << "\n"; add_vertex( g ); // <- in my real application, vertex gets some // properties that depend on source(...) and // target(...) above } } Is it the case that an edge_iterator does not store vertex_descriptors (that should survive reallocation of the vertex storage), but iterators to the vertex storage? What is the proper way to accomplish something like this? My present workaround is to postpone all add_vertex() calls after the loop, but this costs some storage, and with my graph scaling bigger and bigger, that begins to hurt. Any help and explanation is really appreciated! Regards, Julius

3 18

Re: [Boost-users] [boost] [review][constrained_value] Review of ConstrainedValueLibrary begins today
by jesseperla＠gmail.com 10 Dec '08

10 Dec '08

Robert: >First, I hope that you are aware of the issues with using floating point types >with this library. If not, please read the rationale section of the >documentation and the discussion in the related thread on the developers' list. Yup, been following. You did a good job of educating me on a previous post... I think I understand the issue now, but don't really have much of an option. As far as I can undestand from the discussions, this is a general problem with equality operations with floating points and has nothing to do with your library. If this is true, I would change the "rationale" section to say that the mess is not your fault and it isn'ta library problem and that you need to be just as careful as you would normally. >The constraint could look like this (written out of my head, not tested): If this is possible, I am very happy. It looks like it is. The only other things that I would say need to be thought through in the design is unions of constraints instead of just intersections of them. For example, I was checking this out a while back, and it manages the sets of intervals/etc. well: http://www.herold-faulhaber.de/itl/ I would wonder if formalizing intervals in this library (or using another) is a good way to deal with different bounds... but that is beyond my level of competence. > Why not just use numeric_limits<risk_aversion::value_type>? 1) Because I was too stupid to think of that, and 2) Because I want to be able to write generic functions such as: template<typename T> bool is_NaN(T& t) { return (t == std::numeric_limits< T >::quiet_NaN()); } Again, my idea is that I want to be able to throw around elements of constrained types to generic functions and all of the standard types of things I would do with the superset type. >Actually, only the mutating operators (++, --, =, += etc.) are overloaded. For >I don't think this is needed. If you write: > constrained<int> x, y, z; > z = x + y; >Then simply the + operator for int is used. Even better. As long as it works for all of the auto conversions between intrinsic types we are also in business. eg constrained<int> x, y, z; double c; z = c * x + y; Thanks Robert. Great library, time for me to submit a glowing review.

4 4

socket reconnection
by boost001 10 Dec '08

10 Dec '08

I have an ASIO socket server. I need to close the socket and then listen to the socket again if client disconnected from server. When the server was started, the socket and acceptor are initialized like this: asio_socketPtr = new tcp::socket(asio_service); asio_acceptorPtr = new tcp::acceptor(asio_service, tcp::endpoint(protocol, m_iPort)); in the process closing the socket, I did the following in order: asio_acceptorPtr->close(error_closing); asio_socketPtr->shutdown(tcp::socket::shutdown_both, error_closing); asio_socketPtr->close(error_closing); in the process reopen the socket, I did the following in order: asio_socketPtr->open(protocol, error_connecting); asio_acceptorPtr->open(protocol, error_connecting); but I always got error. the error code is 1. It means Operation not permitted. Did I miss something? Do I need to delete above socketPtr and acceptorPtr and create new one each time? thanks, -- View this message in context: http://www.nabble.com/socket-reconnection-tp20922241p20922241.html Sent from the Boost - Users mailing list archive at Nabble.com.

2 3

asio - How do I modify code using old ASIO to newer version?
by Jeff Lee 10 Dec '08

10 Dec '08

Hi , I have some code using the old version of ASIO . some code like this: try { while( mWrapped->mSocket.in_avail() > 0 ) { ... but I found that there is no in_avail() method exist in current version. how can I resolve the problem ? Plz dont just give a web link. I'm using the very very slow internet connection.. so , search from internet or even get the document is difficult.

2 1

[Asio] async_connect leaking memory/handles ?
by Jim Methley 10 Dec '08

10 Dec '08

Hello there, New to the list and using Boost Asio. I've implemented an SSL connection using async_connect ok, but find that it seems to leave resources allocated when completed and the SSL connection object is destroyed. The application using the Boost SSL functionality creates a socket connection as required then releases it. Its running on a windows platform with Microsoft Visual Studio 2008 and Boost 1.36.0. The problem can be easily illustrated by simple modification of http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/example/ssl/cli ent.cpp to place the main functionality in a loop. Then monitoring the process using TaskManager to display Mem Usage and Handles shows both steadily going up. The number of handles increments by 1,2 or 3 on each async_connect. This happens regardless of whether it actually manages to connect or not. A modification to not use SSL has no effect. A further modification to use a synchronous connect and the program then does not bleed resources. Is this a known problem ? Or is there something which I should be releasing myself ? The actual code I tested is shown below. The relevant parts are: 1) main() line 140: while (true) 2) class client() line 32: simple socket connect (resources released ok) 3) class client() line 41: original async_connect (resources not released ok) Any ideas gratefully received ! /Jim // // client.cpp // ~~~~~~~~~~ // // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include <cstdlib> #include <iostream> #include <boost/bind.hpp> #include <boost/asio.hpp> #include <boost/asio/ssl.hpp> using boost::asio::ip::tcp; enum { max_length = 1024 }; class client { public: client(boost::asio::io_service& io_service, boost::asio::ssl::context& context, boost::asio::ip::tcp::resolver::iterator endpoint_iterator) : simpleSocket_(io_service) ,socket_(io_service, context) { boost::asio::ip::tcp::endpoint endpoint = *endpoint_iterator; // This consumes no resources simpleSocket_.connect(endpoint); // This consumes resources // simpleSocket_.async_connect(endpoint, // boost::bind(&client::handle_connect, this, // boost::asio::placeholders::error, // ++endpoint_iterator)); // This original code consumes resources // socket_.lowest_layer().async_connect(endpoint, // boost::bind(&client::handle_connect, this, // boost::asio::placeholders::error, ++endpoint_iterator)); } void handle_connect(const boost::system::error_code& error, boost::asio::ip::tcp::resolver::iterator endpoint_iterator) { std::cout << "handled connect"; return; if (!error) { socket_.async_handshake(boost::asio::ssl::stream_base::client, boost::bind(&client::handle_handshake, this, boost::asio::placeholders::error)); } else if (endpoint_iterator != boost::asio::ip::tcp::resolver::iterator()) { socket_.lowest_layer().close(); boost::asio::ip::tcp::endpoint endpoint = *endpoint_iterator; socket_.lowest_layer().async_connect(endpoint, boost::bind(&client::handle_connect, this, boost::asio::placeholders::error, ++endpoint_iterator)); } else { std::cout << "Connect failed: " << error << "\n"; } } void handle_handshake(const boost::system::error_code& error) { if (!error) { std::cout << "Enter message: "; std::cin.getline(request_, max_length); size_t request_length = strlen(request_); boost::asio::async_write(socket_, boost::asio::buffer(request_, request_length), boost::bind(&client::handle_write, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } else { std::cout << "Handshake failed: " << error << "\n"; } } void handle_write(const boost::system::error_code& error, size_t bytes_transferred) { if (!error) { boost::asio::async_read(socket_, boost::asio::buffer(reply_, bytes_transferred), boost::bind(&client::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } else { std::cout << "Write failed: " << error << "\n"; } } void handle_read(const boost::system::error_code& error, size_t bytes_transferred) { if (!error) { std::cout << "Reply: "; std::cout.write(reply_, bytes_transferred); std::cout << "\n"; } else { std::cout << "Read failed: " << error << "\n"; } } private: tcp::socket simpleSocket_; boost::asio::ssl::stream<boost::asio::ip::tcp::socket> socket_; char request_[max_length]; char reply_[max_length]; }; int main(int argc, char* argv[]) { try { if (argc != 3) { std::cerr << "Usage: client <host> <port>\n"; return 1; } while (true) { std::cout << "Creating service\n"; boost::asio::io_service io_service; boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(argv[1], argv[2]); boost::asio::ip::tcp::resolver::iterator iterator = resolver.resolve(query); boost::asio::ssl::context ctx(io_service, boost::asio::ssl::context::sslv23); ctx.set_verify_mode(boost::asio::ssl::context::verify_peer); ctx.load_verify_file("ca.pem"); client c(io_service, ctx, iterator); io_service.run(); } } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; }

1 1

[Serialization] assertion failure on exit
by Kenny Riddile 09 Dec '08

09 Dec '08

I'm getting the following assertion failure on exit when instantiating certain serializable classes: Assertion failed: NULL != l, file libs\serialization\src\extended_type_info.cpp, line 47 I was finally able to determine a difference between the classes that caused the assertion failure and those that didn't. Here's some code: ////////////////////////////////////////////////////////////////// // Serializable.hpp: class Serializable { public: virtual ~Serializable() = 0; template< typename Archive > void serialize( Archive& /*ar*/, const unsigned int /*version*/ ) { } private: }; inline Serializable::~Serializable() { } BOOST_CLASS_EXPORT( Serializable ) ////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////// // Foo.hpp: struct Foo : Serializable { template< typename Archive > void serialize( Archive& ar, const unsigned int /*version*/ ) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP( Serializable ); } }; BOOST_CLASS_EXPORT( Foo ) ////////////////////////////////////////////////////////////////// The above code does not assert on exit after instantiating a Foo object. If I make Foo not header-only like so: ////////////////////////////////////////////////////////////////// // Foo.hpp: struct Foo : Serializable { Foo(); template< typename Archive > void serialize( Archive& ar, const unsigned int /*version*/ ) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP( Serializable ); } }; BOOST_CLASS_EXPORT( Foo ) ////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////// // Foo.cpp: Foo::Foo() { } ////////////////////////////////////////////////////////////////// then I get the assertion failure on program exit if I so much as instantiate a Foo object.

4 8

asio - how to reuse existing socket descriptor?
by QPlace 09 Dec '08

09 Dec '08

I am porting Win32 C++ application to use boost asio library. In this application I have a client socket that is returned to me from the call to 3-rd party library. Then I am getting data from the connection using WSAAsyncSelect, where the first parameter is the socket handle. My question: Is there any way to use asio library to read data from already established connection where I know the client socket handle? I cannot initiate connection myself, it is only done through 3-rd party library, I only know client socket descriptor. Any help/comments will be greatly appreciated.

2 1

why does subversion checkout refer only to 1.34?
by Robert P. J. Day 09 Dec '08

09 Dec '08

i checked out the svn trunk for boost and, while i read that the latest version of boost is 1.37, the README.txt file refers only to 1.34.0. can someone clarify this? thanks. rday -- ======================================================================== Robert P. J. Day Linux Consulting, Training and Annoying Kernel Pedantry: Have classroom, will lecture. http://crashcourse.ca Waterloo, Ontario, CANADA ========================================================================

1 0

asio::deadline_timer::expires_at problem when system time changes
by Jeff Gray 09 Dec '08

09 Dec '08

My application is running on an embedded system that has no battery backed up real time clock. So when it starts, it's always 1-1-1970. The first time a client app connects, it synchronizes the time, so the system time will change to 2008. This has drastic consequences on this sort of action: void MyClass::TimerCallback(void) { // do important periodic activity here... myTimer->expires_at(myTimer->expires_at()+ boost::posix_time::milliseconds(100)); myTimer->async_wait(boost::bind(&MyClass::TimerCallback, this)); } Since the expires_at() values is absolute time, it still thinks it's 1970, moving forward 100mS at a time. This causes the timer to expire immediately, and my CPU load goes to 100% as it gets stuck in this repetition. This is not a bug on the part of deadline_timer - it's doing exactly what I told it to. The question is how should I change the code to cope with time changes. I see several options: 1) The API call to set the time on my embedded device is within my application, so I know when an outside party has changed the time. I could send a boost::signal to the rest of the application & wrote code in each module that has a deadline timer used in this way that resets the timer. 2) Before setting a new expires_at value, I could calculate the time period between now() and expires_at(). If it is more than double the periodic delay, then I use expires_from_now() to resync with the new absolute time. 3) I could calculate the periodic time based on absolute time: now() - (now() % milliseconds(100)) + milliseconds(100) This means it would always be aligned with the most recent 100mS time. 4) Only use expires_from_now(). This is the simplest solution, but there are parts of my application where it is preferable to have more accurate timer period. These approaches all have advantages and drawbacks. Does anyone have any comments or experience with this issue? Thanks, Jeff

3 3

Re: [Boost-users] [boost] [review][constrained_value] Review of ConstrainedValueLibrary begins today
by Jesse Perla 09 Dec '08

09 Dec '08

I wasn't sure if anyone was allowed to review, but if so, then all of my questions have been answered: Library Review: > > - What is your evaluation of the design? I can't comment on it as a generic library designer, but as a library user it appears to be an excellent framework. However, the use cases for bounds checking of variables are much more thought through than the more interesting mathematics/set theory and numerics use cases. I think the library seems to be close to supporting these use cases but needs to explicitly address: 1) Floating Points: Enough has been said about this, but it needs to be resolved before the library is completed. Otherwise, all mathematics/numerics use cases are impossible. As a pragmatist about this issue, I would say that a worst case "solution" is to write caveats in the "rationale" section about this problem when using this library. This library is useful for querying bounds on a type, even if it doesn't do any bounds checking. 2) Dynamic Bounded Types: Right now the static bounds are associated globally with a type, and the dynamic bounds are associated with an instance of a type. Since many use cases involve setting dynamic sets and then creating instances, it is crucial that this type of set is implemented. See Robert's rough notes in: http://lists.boost.org/boost-users/2008/12/42959.php 3) Representing Disjoint Sets: Because most of the use cases have been thinking about predicates and bounds checking, the key use cases of unions of bounds has not been addressed. In most of the discussions, people talk about layering constraints on top of each other, which is an intersection. This library needs to also have ways to easily create sets like: (-infinity, 0] union [1,2] union [3,infinity) This would be a union of constraints which could be set or accessed on the type (at runtime or compiletime), hopefully with simple iterators to access this type information. I think that thinking through closed/open/halfopen/etc. intervals as separate objects in themselves is critical, especially to layer this type of bound on. Perhaps it could be integrated with the interval template library in the sandbox for example. 4) Testing with Numerics: This library needs to be tested with key boost numeric packages such as ublas, boost math, accumulators, etc. The key here will also be to verify that it compiles with the static and dynamic bounded types, the storage is identical to the underlying type, and the operations it generates are not any slower. Also that all of the elementary operators on intrinsic types in C++ work as normal for by value/ref/pointer, numeric_limits is thought through, etc. All of the former is performance/storage testing would be conditional on a good compiler of course (gnu and Intel seem to be the main ones to worry about) > - What is your evaluation of the implementation? For the existing constraint types, it looks good. > - What is your evaluation of the documentation? Good for the simple cases here and the bounds checking. Incomplete for the key math/numerics use cases which is where this would be at its best. And the floating point section would need to be rewritten after it is "solved". > - What is your evaluation of the potential usefulness of the library? Extraordinarily useful for generic mathematics/numerics. Even without any bounds checking, managing subsets of intrinsic types with runtime bounds information has a huge value. And having domains/ranges associated with functions would save a huge number of bugs in numeric processing, as well as make the translation from blackboard to program much more elegant. This could be a cornerstone of allowing for safe implementations of mathematical models in disciplines such as economics. For example, an optimizer operating on bounded values could create a grid from just the passed in type, validate if a solution is converging to an open set bound, etc. And higher order functors such as derivatives could generate domain/range information for the functions they are operating on dynamically. > - Did you try to use the library? With what compiler? Did you have any > problems? No. It doesn't yet have the main constraint type I am interested in. > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? I had previously been writing notes on a library to manage domain/range information for functors that this becomes a superset of, so I have thought through a large number of those use cases. A great deal of time was spent trying to see how this library could fit the use cases I am interested in. > - Are you knowledgeable about the problem domain? > For generic library design: little knowledge. For the bounds-checking, value monitoring use cases: little knowledge. For the mathematics/numerics use cases: A good deal of knowledge as I am working through many of these issues in projects/research and trying to build out domain specific libraries to make future research easier.. > Please state in your review, whether you think the library should be > accepted as a Boost library. Yes, conditional on solving the 1) to 4) design questions above. Robert has posted excellent starting points for many of these topics.

4 3

[random]how to initialise a rng for use in the initialiser list?
by Moritz Beber 09 Dec '08

09 Dec '08

Hello again, sorry for the many questions to this list right now, I'm just beginning to use boost. This time I have some issues regarding the boost.random usage. I have used it just fine for many examples but there's one tricky bit that I was wondering whether anyone of you knows a solution for. I use a class which keeps the random number generator around as a member variable; this class also has a const matrix. Now in the constructor of the class I do something like: my_class::my_class(args) : rng(seed), matrix(initialise()), ... { ... } Of course, I want to use the rng to initialise the matrix and that's where things fail. I guess, I could use a different rng just to fill the matrix, or make it non-const and fill it in the constructor body. But does anyone know a neat trick to do this in the way proposed? Thank you for any answers, Moritz

4 5

boost asio async_read_som
by Chris Freehill 08 Dec '08

08 Dec '08

Never mind... I finally realized io_service.run() exits if there is no work to do. I was misunderstood and thought it stayed running. Thanks, Chris -- =======================

1 0

logfile write/poll mechanism
by Thijs Koerselman 08 Dec '08

08 Dec '08

Hi, This might not be a Boost question. I'm not sure. I have 2 independent applications. One is writing information to a log file somewhere, the other contains a console window. What I would like to do is poll the log file from the application with the console window, and write any new lines (since last poll) to the window. It's seems like a fairly trivial thing to implement, but I don't have a lot of experience dealing with files, and I suspect there are already facilities to do such a thing. Can someone please point me in the right direction? Cheers, Thijs

2 2

Re: [Boost-users] boost asio async_read_some
by Chris Freehill 08 Dec '08

08 Dec '08

Igor, Thanks for the response. I've been out for a few days, so I haven't been able to reply. Here is a self-contained example that illustrates the problem. This example creates a echo server thread that should echo back to the caller anything the caller sends to the thread. (Note that I have a windows Sleep() in there.) The server thread appears to do what I expect. The client thread works until the call to async_read_some(). The call returns, but I never hit the breakpoint I set in my handler, nor do I see any output from the handler. Igor, or anyone, please have a look... Thanks, Chris =============================================START================================================== #include <string> #include <boost/asio.hpp> #include <boost/bind.hpp> #include <boost/smart_ptr.hpp> #include <boost/thread.hpp> const static unsigned int cMaxLength = 512; static const std::string cStopEchoCommand("STOP_ECHO"); static boost::asio::io_service ioService; //needs to have the same life span as socket, or longer static boost::asio::ip::tcp::resolver lResolver(ioService); //------------------------------------------------------------------------------------------------- static int doConnect(std::string& ipAddress, std::string& portNumber, boost::shared_ptr<boost::asio::ip::tcp::socket>& inOutSocket) { using boost::asio::ip::tcp; try { tcp::resolver::query query(tcp::v4(), ipAddress.c_str(), portNumber.c_str()); tcp::resolver::iterator endpoint_iterator = lResolver.resolve(query); tcp::resolver::iterator end; if (inOutSocket == NULL) { boost::shared_ptr<tcp::socket> tmpSocketPtr(new tcp::socket(ioService)); inOutSocket = tmpSocketPtr; } boost::system::error_code error = boost::asio::error::host_not_found; while (error && endpoint_iterator != end) { inOutSocket->close(); inOutSocket->connect(*endpoint_iterator++, error); } if (error) { return -1; } } catch(...) { return -1; } return 0; } //Server routine static void session(unsigned int port) { using boost::asio::ip::tcp; boost::asio::io_service io_service; tcp::acceptor a(io_service, tcp::endpoint(tcp::v4(), port)); tcp::socket sock(io_service); try { bool done = false; a.accept(sock); for (;;) { char data[cMaxLength]; boost::system::error_code error; size_t length = sock.read_some(boost::asio::buffer(data, cMaxLength), error); if (error == boost::asio::error::eof) { // done, stop echoing, wait for another connection break; } else if (error) { std::cerr << "Error while receiving: " << boost::system::system_error(error).what() << "\n"; // TODO report failure break; // closing. } else if (length == cStopEchoCommand.length()) { //See if it's time to end if (cStopEchoCommand.compare(0, cStopEchoCommand.length(), data)) { break; } } else { //boost::asio::write(sock, boost::asio::buffer(data, length)); int bytesWritten = sock.write_some(boost::asio::buffer(data, length)); if (bytesWritten == 0) { std::cerr << "Error while writing to socket: " << boost::system::system_error(error).what() << "\n"; } } } } catch (std::exception& e) { // TODO report failure std::cerr << "Exception in thread: " << e.what() << "\n"; } } class TestClass { public: TestClass(std::string ipAddress, std::string port):mIPAddress(ipAddress), mPort(port) {} void PollReadhandler(const boost::system::error_code& error, size_t bytes_transferred) { mDataReadFromPoll = true; boost::system::error_code e; std::cout << "DELETE ME; PollReadhandler called()" << "\n"; } void testTCPIP() { using boost::asio::ip::tcp; // Start an separate thread which echoes all trafic to the port. std::istringstream i(mPort); unsigned int port; i >> port; mDataReadFromPoll = false; boost::thread echoTcpServer(boost::bind(session, port)); boost::shared_ptr<tcp::socket> socketPtr; int ret = doConnect(mIPAddress, mPort, socketPtr); if (ret) { std::cerr << "Failed to get connection" << std::endl; return; } //------------------------------------------------------------------------------------------------- // test sync. read char buffer[512]; unsigned int bytesRead; std::string test1Str("Test 1"); std::size_t len = socketPtr->write_some(boost::asio::buffer(test1Str.c_str(), test1Str.length())); Sleep(1000); //Windows try { int readError = 0; std::vector<unsigned char> readVectorBuffer(32); //unsigned char readVectorBuffer[512]; boost::system::error_code e; //unsigned int amtRead = socketPtr->read_some(boost::asio::buffer(readVectorBuffer, 512), e); unsigned int amtRead = socketPtr->read_some(boost::asio::buffer(readVectorBuffer, 32), e); if (amtRead != test1Str.length()) { std::cerr << "read_some read an unexpected number of bytes" << std::endl; return; } std::string s(readVectorBuffer.begin(),readVectorBuffer.end()); std::cout << "read_some returned:" << s << std::endl; } catch (...) { std::cerr << "Problem with read_some" << std::endl; } //------------------------------------------------------------------------------------------------- // test async. read std::string test2Str("Test 2"); len = socketPtr->write_some(boost::asio::buffer(test2Str.c_str(), test2Str.length())); Sleep(1000); //Poll while (!mDataReadFromPoll) { socketPtr->async_read_some(boost::asio::buffer(buffer, 512), boost::bind(&TestClass::PollReadhandler, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); Sleep(1000); } //NEVER REACHES HERE mDataReadFromPoll = false; len = socketPtr->write_some(boost::asio::buffer(cStopEchoCommand.c_str(), cStopEchoCommand.length())); // Wait until the server thread is finished. echoTcpServer.join(); } //------------------------------------------------------------------------------------------------- private: std::string mIPAddress; std::string mPort; bool mDataReadFromPoll; }; int main() { TestClass testCase("127.0.0.1", "2222"); testCase.testTCPIP(); } =============================================END==================================================== ---------- Forwarded message ---------- From: "Igor R" <boost.li...(a)gmail.com> Date: Dec 4, 1:44 am Subject: boost asio async_read_some To: BOOST Archives _______________________________________________ Boost-users mailing list Boost-us...@lists.boost.orghttp://lists.boost.org/mailman/listinfo.cgi/boost-users > Here's a simplified version of my call and handler: > unsigned char tmpBuffer[512]; //global > void MyClass::handler(const boost::system::error_code& error, size_t > bytes_transferred) > { > boost::system::error_code e; > std::cerr << "handler called()" << "\n"; > } > void MyClass::test() > { > ... > socketPtr->async_read_some(boost::asio::buffer(tmpBuffer, 512), > boost::bind(&MyClass::handler, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred)); > } > Can anyone give me any idea as to how I can get my handler to be called? Could you please provide some code-excerpt that should compile and work? I.e. code that contains socket initialization, io_service run and your object creation - because the mistake is probably somewhere at those points. > Invocation of the handler will be performed in a > manner equivalent to using boost::asio::io_service::post()." I'm not > sure exactly what this means...what is this equivalent manner that is > mentioned? It means that the handler would be invoked in one of the threads that run the io_service object used by the socked.- Hide quoted text - - Show quoted text -

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Solving sets of interval valued nonlinear equations with Boost Interval?
by Peter H. Hodges 08 Dec '08

08 Dec '08

Does anyone have an example of solving sets of nonlinear interval valued equations using the Boost Interval library functions? Peter Hodges

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boost on windows cmd prompt
by praveen Buddhi 08 Dec '08

08 Dec '08

Hi, I am trying to use boost for my application and builds using command prompt on windows. I am using VC8.0 1) when I invoke build for the my code..i see the following error messages. Any clue?? "Unknown compiler version - please run the configure tests and report the results D:\boost\boost_1_34_1\boost/type_traits/is_integral.hpp(60) : error C2039: 'ulong_long_type' : is not a member of 'boost' D:\boost\boost_1_34_1\boost/type_traits/is_integral.hpp(60) : error C2065: 'ulong_long_type' : undeclared identifier D:\boost\boost_1_34_1\boost/type_traits/is_integral.hpp(60) : error C2913: explicit specialization; 'boost::is_integral' is not a specialization of a class template D:\boost\boost_1_34_1\boost/type_traits/is_integral.hpp(60) : error C2913: explicit specialization; 'boost::is_integral' is not a specialization of a class template D:\boost\boost_1_34_1\boost/type_traits/is_integral.hpp(60) : error C2913: explicit specialization; 'boost::is_integral' is not a specialization of a class template" 2) how to run $BOOST_ROOT/libs/configure on windows command prompt ?? appreciate any help. regards, praveen

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Subject::[boost thread] does a thread block itself when it passes the conditional variable to another thread?
by Lei (oddo) Zhang 08 Dec '08

08 Dec '08

inside a thread, if the conditional variable is changed to satisfy another thread which is on the waiting thread list. Does the current thread give up the global mutex and blocks itself until another thread gives up the mutex? boost::mutex mutex; boost::condition cond; bool data_ready=false; : void thread1(){ boost::mutex::scoped_lock lock(mutex); ...//do some work data_ready=true; cond.notify_one() //assume the condition is satisfied. //do more work -------my question is will this part continue? or thread2 will wake up and block thread 1? } void thread2(){ boost::mutex::scoped_lock lock(mutex); while ( !data_ready) { cond.wait(lock); } ....//do work } -- Lei(Oddo) Zhang 70 Symonds Street Engineering Science Department

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[Graph] call of overloaded 'target(...)' is ambiguous
by Tim Keitt 08 Dec '08

08 Dec '08

I've hit the wall with the Graph library. I cannot seem to resolve the error shown below. This is probably my rather limited experience with complicated template parameters. What is the first thing to try with these sorts of errors? My graph classes do not define source and target, but rely on the template provided in the Graph library. I've tried adding them explicitly to the class without success. The 'target' template is defined as: template <typename G> typename filtered_graph_base<G>::vertex_descriptor target(typename filtered_graph_base<G>::edge_descriptor e, const filtered_graph_base<G>& g) { return target(e, g.m_g); } The ambiguous call to 'target' occurs here: template <class PredEdgeMap, class Tag> struct edge_predecessor_recorder : public base_visitor<edge_predecessor_recorder<PredEdgeMap, Tag> > { typedef Tag event_filter; edge_predecessor_recorder(PredEdgeMap pa) : m_predecessor(pa) { } template <class Edge, class Graph> void operator()(Edge e, const Graph& g) { put(m_predecessor, target(e, g), e); } PredEdgeMap m_predecessor; }; Notice that the 'target' template takes one parameter ('G') and the 'operator()' template takes two parameters ('Edge' and 'Graph'). Notice also below the occurrence of both 'G' and 'Graph' in the 'candidates are' section. Might this be fixed as: template <class Graph> void operator()(typename Graph::edge_descriptor e, const Graph& g) { put(m_predecessor, target(e, g), e); } ??? THK /usr/include/boost/graph/edmunds_karp_max_flow.hpp:232: instantiated from 'typename boost::detail::edge_capacity_value<Graph, P, T, R>::type boost::edmunds_karp_max_flow(Graph&, typename boost::graph_traits<G>::vertex_descriptor, typename boost::graph_traits<G>::vertex_descriptor, const boost::bgl_named_params<P, T, R>&) [with Graph = FlowCapacitySQLDiGraph, P = edge_index_property_map<FlowCapacitySQLDiGraph, double>, T = boost::edge_residual_capacity_t, R = boost::no_property]' postgraph.cpp:1092: instantiated from here /usr/include/boost/graph/visitors.hpp:176: error: call of overloaded 'target(FlowCapacitySQLDiGraph::edge_descriptor&, const boost::filtered_graph<FlowCapacitySQLDiGraph, boost::is_residual_edge<edge_index_property_map<FlowCapacitySQLDiGraph, double> >, boost::keep_all>&)' is ambiguous /usr/include/boost/graph/filtered_graph.hpp:322: note: candidates are: typename boost::filtered_graph_base<G>::vertex_descriptor boost::target(typename boost::filtered_graph_base<G>::edge_descriptor, const boost::filtered_graph_base<Graph>&) [with G = FlowCapacitySQLDiGraph] /usr/include/boost/graph/graph_traits.hpp:154: note: T std::target(std::pair<_ForwardIterator, _ForwardIterator>, const G&) [with T = unsigned int, G = boost::filtered_graph<FlowCapacitySQLDiGraph, boost::is_residual_edge<edge_index_property_map<FlowCapacitySQLDiGraph, double> >, boost::keep_all>] make: *** [postgraph.o] Error 1 -- Timothy H. Keitt http://www.keittlab.org/

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[Asio] Cannot receive a UDP multicast using receive_from
by David Laurie 08 Dec '08

08 Dec '08

Would like to say Hello to all as I've just joined the list today and am also a first time user of the boost libraries. I'm cutting my teeth on asio by trying to receive a UDP multicast message with the boost::asio::ip::udp::socket::receive_from function. I got it going using the windows calls but just cant seem to crack it with boost. My only suspicion is that im getting the wrong IP version in the endpoint, but would guess it has found it from the initialisation, but other than that im a bit stumped. Any suggestions to where I may be going wrong? Cheers David Heres the code: const boost::asio::ip::address listen_address = boost::asio::ip::address::from_string("192.168.1.1"); const boost::asio::ip::address multicast_address = boost::asio::ip::address::from_string("224.x.x.x"); //appropriate address used boost::asio::io_service io_service; boost::asio::ip::udp::socket socket_(io_service); boost::asio::ip::udp::endpoint sender_endpoint_; enum { max_length = 1024 }; char data_[max_length]; // Create the endpoint boost::asio::ip::udp::endpoint listen_endpoint( listen_address, multicast_port); // open the socket socket_.open(listen_endpoint.protocol()); // is this picking up v6 instead of v4? // Join the multicast group. socket_.set_option( boost::asio::ip::multicast::join_group(multicast_address)); // bind it socket_.bind(listen_endpoint); socket_.receive_from( boost::asio::buffer(data_, max_length), sender_endpoint_); This email has been scanned for all known viruses by the MessageLabs Email Security System. Systems Engineering & Assessment Ltd - Beckington Castle, 17 Castle Corner, Beckington, Frome, Somerset, BA11 6TA, UK is registered in England and Wales with the company number 2430846. The contents of this email (including any attachments) are confidential and may be legally privileged. If you are not the intended recipient of this email any disclosure, copying, distribution or use of its contents is strictly prohibited. You should notify the sender immediately and then delete it (including any attachments) from your system. Please help out the environment by only printing this e-mail if absolutely necessary - Thank You.

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Subject::[boost thread] when does the thread start?
by Lei (oddo) Zhang 08 Dec '08

08 Dec '08

When I create a thread object such as : boost::thread thrd1(boost::bind(&function)); does the thread start executing the function immediately? -- Lei(Oddo) Zhang 70 Symonds Street Engineering Science Department

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Build error: "duplicate initialization of gcc"
by Tim Martin 08 Dec '08

08 Dec '08

I downloaded boost 1.37.0, unzipped and ran $ ./configure $ make install It dies reliably with: ------------------ ./tools/jam/src/bin.linuxx86/bjam -sICU_PATH=/usr --user-config=user-config.jam --prefix=/home/timm --exec-prefix=/home/timm --libdir=/home/timm/lib --includedir=/home/timm/include install error: at /home/timm/downloads/boost_1_37_0/tools/build/v2/build/project.jam:846 error: duplicate initialization of gcc with the following parameters: error: version = 4.3.2 error: previous initialization at /home/timm/downloads/boost_1_37_0/tools/build/v2/build/project.jam:846 Not all Boost libraries built properly. ------------------- This is on a relatively unmodified Ubuntu Intrepid linux install. I could only find one other mention of this problem on the web and it was a mailing list post with no answer, so I'm apparently doing something quite unusually wrong. FWIW, the reason I'm building from source rather than using a package is that the Ubuntu packages don't seem to provide a binary lib for MPI - am I missing something here? They provide header files, so it seems eccentric not to provide a package with libs. Tim

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Re: [Boost-users] [boost] [review][constrained_value] Review of ConstrainedValueLibrary begins today
by jesseperla＠gmail.com 07 Dec '08

07 Dec '08

Robert: As a caveat and analogy: I want to use this to represent mathematics rather than just bounds-checking. The constrained value manages the subset within an underlying space (represented by the underlying type int, double, etc.). Then an instantiation of this is an element in this set. And my goal is to be able to take an instantiation/element and access information about the underlying set/type itself (eg managing bounds for optimizers, domain/range for functors, etc. from only an instance of the type passed in to a generic function). And if you use linear operators on elements of the subset, then it always returns members of the underlying space (which is mathematically correct. integers are a subset of reals which is a linear space with the +,-,/,* operators on it. Divide an integer by an integer and you get an element of the superset) More questions: 1) Storage the same as underlying type?::::::: > OK, now it makes a bit more sense. Moreover, I believe it is possible (though > maybe not trivial) to implement something similar with the current library. Cool. This would be necessary for me to use the library, so I hope it is possible to have dynamic bounds associated with the type. If this was completed, would the space/storage taken up by an instantiation of the bounded type be the same as the underlying type? In particular, I would be interested in having a vector of bounded double's have the same storage aa vector of bounded doubles (I would be using ublas for example) so that I could potentially pass on a pointer to a C function for some interoperability (I know... hacky but sometimes necessary for all the C scientific computing libraries out there). And for my numerical work, having an extra parameter or two stored for every value in a big matrix would eat up cache/memory too quickly for no value. If necessary to accommodate consistency of the storage with just the underlying type, perhaps the idea of a bounded value on an instantiation (like it is today for the runtime) vs. a bounded type (modifiable at runtime, but common to all instance) could have a different template... something like: typedef bounded_type<double, "INTEREST RATE"> interest_rate; interest_rate::change_bounds(.8, .99); 2) Casting for underlying numeric type?:::::::::: > http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2199.html Thanks for educating me on this. I find the myvar.value() syntax to be a little rough since my functions would want to be able to use both bounded types and intrinsic types in the same function, but perhaps this could work with an explicit cast which seems reasonable considering the C++ limitation. For example, would something like the following work to ensure consistency in my own usage?: template<typname T> void myfunc1(T& t) { cout << std::max(0.0, static_cast<double>(t)); //Note a floating point here } void myfunc2(T& t) { cout << std::max(0, static_cast<int>(t)); //Note integer here. } typedef bounded_type<double, "INTEREST RATE"> interest_rate; interest_rate::change_bounds(.8, .99); interest_rate r = .95; myfunc1(r); //works since casting internal myfunc1(.75); //also works, may be a double to double cast... myfunc2(r); //Would this fail? myfunc2(1); //Should work Note on the last one that it is trying to call max with an integer... My question here is whether this would work? Does the constrained value only have a direct cast to its underlying type, or is there any way to have it cast to any types that the underlying type can cast to? I would guess not for the last case... and this may be where myvar.value() is absolutely necessary? If the casting to the underlying type always works, then I would suggest that the myvar.value() is not the right way to go about things. What we are talking about here really is a cast, like it or not. 3) Bounds including infinity?:::::::: When we are working with bounds, can we use the numeric infinities with both open and closed sets? I am thinking something like: typedef bounded_type<double, "Risk Aversion"> risk_aversion; risk_aversion::change_bounds(1, std::numeric_limits<double>::infinity()); //Might want open or closed depending on if function domain is reals or extended reals. 4) Numeric limits traits?:::::::::::: For numeric processing, we also need to have some association with the numeric limit traits. I realize that there is some kind of conceptual connection between some of the traits here and the bounds themselves, but for practical purposes, these traits are too useful to ignore. Conceptually I think of these traits as being information about how the data is stored, rather than bounds themselves. What would be really useful is if bounded<> and other types would generate traits on their own based on the underlying type... this way, we wouldn't have to create numeric_limits traits for the types ourselves (which is unreasonable for a library user). So what I am thinking of is; typedef bounded_type<double, "Risk Aversion"> risk_aversion; cout << numeric_limits<risk_aversion>::quiet_NaN(); where the numeric_limits<risk_aversion> subclasses directly from numeric_limits<double>..... I don't know enough about generic programming to know how or if this is possible, but this is necessary for generic numeric programming. 5) Testing set inclusion:::::::: While it is nice to have the bounds checking on the () operator, I would also want to be able to ask the type if a value is in the set. For example, in math: Let Y = integers Let X = positive integers y = -1 \in Y Is y \in X? In this: typedef bounded_type<int, "X"> X; X::change_bounds(0, std::numeric_limits<int>::infinity()); int y = -1; cout << X::element_of(y); //would return a boolean? what I really would love to say is is X::element_of() or element_of<X>(y) ? This is a non-failing operation, and would be used all over in my numeric code, especially with wrapping optimizers. 6) No debug only functionality please:::::::::::: On all of the conversations about turning off bounds checking on debug, I would definitely not want this to happen automatically. And a bounds checking failure should be an exception, not a non-recoverable error. I may want to use this with an optimizer that tries to put in values out of bounds, and I would want to catch it and display a message to the console that the optimization failed, then try with a different initial value. 7) Operations consistent with built in C++ numeric types::::::::::::::::::: You have successfully educated me on why you need to overload the ++, --, +, -, etc. operators yourself and can't just revert to the underlying type. But focusing entirely on intrinsic numeric types double, int, etc.: Will we have complete coverage of the operators that are defined for these types in C++? Will the compiler end up generating EXACTLY the same code if I do a whole bunch of read only operations on a bounded<double> vs. a double? And will the overloading of these operators work for cross-type operations (eg multiplying a constrained integer by a constrained double?)? If the answer is no on these, then we probably can't use this library for scientific processing. 8) Multi-bounds:::::::::::::::: In comments such as: http://lists.boost.org/Archives/boost/2008/12/145662.php I think this is getting away from what I would hope this library can achieve: Associating sets(in the mathematical sense) of allowed values with a C++ type. I see what the predicates are used for, but I wouldn't use them very often. So I don't think we can think of the multi-bounds here being orthogonal constraints, but rather being a set of disconnected intervals themselves. Why not orthogonal constraints as described in this link (which essentially means intersections of subsets)? Try to construct X = (-infinity, 0] union [1,2] union [3,infinity) with intersecting intervals.... I would love to have a list of disconnected intervals in the space of the underlying type that could be parsed through from the . I do not see this as primarily a predicate question. If this is done with iterators, it might be even more flexible. For example, say that you only wanted even numbers and wanted to list out the first 10 intervals of this set... it could return an iterator to a list of intervals. In this case, it wouldn't calculate all of the intervals at once, but when you stepped forward, it would give you the next valid interval (a single value in this case). Thanks, Jesse

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